diff --git a/README.md b/README.md
index 2e42a57..b77461d 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ Specifications for dimensional units are in the [UnitSystems.jl](https://github.
 The three packages are designed so that they can be interchanged with compatibility.
 On its own `UnitSystems` is the fastest package, while `Similitude` (provides `Quantity` type) and `MeasureSystems` (introduces [Measurements.jl](https://github.com/JuliaPhysics/Measurements.jl) uncertainty) build additional features on top of `UnitSystems` base defintions.
 Additionally, in the `UnitSystems` repository there is an equivalent [Wolfram language paclet](https://reference.wolfram.com/language/guide/Paclets) `Kernel` and also an unmaintained Rust `src` implementation.
-Defaults are shared: `Metric`, `SI2019`, `CODATA`, `Conventional`, `International`, `InternationalMean`, `MetricTurn`, `MetricGradian`, `MetricDegree`, `MetricArcminute`, `MetricArcsecond`, `MetricEngineering`, `GravitationalMetric`, `FPS`, `IPS`, `British`, `English`, `Survey`, `Gauss`, `LorentzHeaviside`, `EMU`, `ESU`, `IAU`, `IAUE`, `IAUJ`, `Hubble`, `Cosmological`, `CosmologicalQuantum`, `Meridian`, `Nautical`, `MPH`, `KKH`, `MTS`, `FFF`, `Planck`, `PlanckGauss`, `Stoney`, `Hartree`, `Rydberg`, `Schrodinger`, `Electronic`, `Natural`, `NaturalGauss`, `QCD`, `QCDGauss`, `QCDoriginal`.
+Defaults are shared: `Metric`, `SI2019`, `CODATA`, `Conventional`, `International`, `InternationalMean`, `MetricTurn`, `MetricGradian`, `MetricDegree`, `MetricArcminute`, `MetricArcsecond`, `Engineering`, `Gravitational`, `FPS`, `IPS`, `British`, `English`, `Survey`, `Gauss`, `LorentzHeaviside`, `EMU`, `ESU`, `IAU`, `IAUE`, `IAUJ`, `Hubble`, `Cosmological`, `CosmologicalQuantum`, `Meridian`, `Nautical`, `MPH`, `KKH`, `MTS`, `FFF`, `Planck`, `PlanckGauss`, `Stoney`, `Hartree`, `Rydberg`, `Schrodinger`, `Electronic`, `Natural`, `NaturalGauss`, `QCD`, `QCDGauss`, `QCDoriginal`.
 
 ```Julia
 julia> using UnitSystems # or Similitude or MeasureSystems
@@ -53,7 +53,7 @@ Standardized unit/derived quantities are `hyperfine`, `loschmidt`, `wienwaveleng
 
 Standard physics units are at https://geophysics.crucialflow.com/dev/units
 
-Additional reference `UnitSystem` variants: `EMU`, `ESU`, `Gauss`, `LorentzHeaviside`, `SI2019`, `SI1976`, `CODATA`, `Conventional`, `International`, `InternationalMean`, `MetricEngineering`, `GravitationalMetric`, `IAU`, `IAUE`, `IAUJ`, `FPS`, `IPS`, `British`, `Survey`, `Hubble`, `Cosmological`, `CosmologicalQuantum`, `Meridian`, `Nautical`, `MPH`, `KKH`, `MTS`, `FFF`; and natural atomic units based on gravitational `coupling` and `finestructure` constant (`Planck`, `PlanckGauss`, `Stoney`, `Hartree`, `Rydberg`, `Schrodinger`, `Electronic`, `Natural`, `NaturalGauss`, `QCD`, `QCDGauss`, and `QCDoriginal`).
+Additional reference `UnitSystem` variants: `EMU`, `ESU`, `Gauss`, `LorentzHeaviside`, `SI2019`, `SI1976`, `CODATA`, `Conventional`, `International`, `InternationalMean`, `Engineering`, `Gravitational`, `IAU`, `IAUE`, `IAUJ`, `FPS`, `IPS`, `British`, `Survey`, `Hubble`, `Cosmological`, `CosmologicalQuantum`, `Meridian`, `Nautical`, `MPH`, `KKH`, `MTS`, `FFF`; and natural atomic units based on gravitational `coupling` and `finestructure` constant (`Planck`, `PlanckGauss`, `Stoney`, `Hartree`, `Rydberg`, `Schrodinger`, `Electronic`, `Natural`, `NaturalGauss`, `QCD`, `QCDGauss`, and `QCDoriginal`).
 
 Unit conversion documentation is at https://geophysics.crucialflow.com/dev/convert
 
diff --git a/src/UnitSystems.jl b/src/UnitSystems.jl
index c383dde..3de9c45 100644
--- a/src/UnitSystems.jl
+++ b/src/UnitSystems.jl
@@ -19,7 +19,7 @@ module UnitSystems
 import Base: @pure, length, time, angle, rem
 import Base.MathConstants: eulergamma, golden, φ
 
-const Systems = (:Metric,:SI2019,:SI1976,:CODATA,:Conventional,:International,:InternationalMean,:MetricTurn,:MetricSpatian,:MetricGradian,:MetricDegree,:MetricArcminute,:MetricArcsecond,:MetricEngineering,:GravitationalMetric,:MTS,:EMU,:ESU,:Gauss,:LorentzHeaviside,:FPS,:IPS,:British,:English,:Survey,:FFF,:MPH,:KKH,:Nautical,:Meridian,:IAU☉,:IAUE,:IAUJ,:Hubble,:Cosmological,:CosmologicalQuantum,:Planck,:PlanckGauss,:Stoney,:Hartree,:Rydberg,:Schrodinger,:Electronic,:Natural,:NaturalGauss,:QCD,:QCDGauss,:QCDoriginal)
+const Systems = (:Metric,:SI2019,:SI1976,:CODATA,:Conventional,:International,:InternationalMean,:MetricTurn,:MetricSpatian,:MetricGradian,:MetricDegree,:MetricArcminute,:MetricArcsecond,:Engineering,:Gravitational,:MTS,:EMU,:ESU,:Gauss,:LorentzHeaviside,:FPS,:IPS,:British,:English,:Survey,:FFF,:MPH,:KKH,:Nautical,:Meridian,:IAU☉,:IAUE,:IAUJ,:Hubble,:Cosmological,:CosmologicalQuantum,:Planck,:PlanckGauss,:Stoney,:Hartree,:Rydberg,:Schrodinger,:Electronic,:Natural,:NaturalGauss,:QCD,:QCDGauss,:QCDoriginal)
 const Dimensionless = (:coupling,:finestructure,:electronunit,:protonunit,:protonelectron,:darkenergydensity)
 const Constants = (:lightspeed,:planck,:planckreduced,:electronmass,:molarmass,:boltzmann,:vacuumpermeability,:rationalization,:lorentz,:luminousefficacy,:gravity,:radian)
 const Physics = (:turn,:spat,:dalton,:protonmass,:planckmass,:gravitation,:gaussgravitation,:einstein,:hartree,:rydberg,:bohr,:electronradius,:avogadro,:molargas,:stefan,:radiationdensity,:vacuumpermittivity,:electrostatic,:magnetostatic,:biotsavart,:elementarycharge,:faraday,:vacuumimpedance,:conductancequantum,:klitzing,:josephson,:magneticfluxquantum,:magneton)
@@ -132,7 +132,7 @@ additional constants `molarmass`, `luminousefficacy`, `gravity`, `radian`, `turn
 
 Standardized unit/derived quantities are `$(listext(Derived))`.
 
-Additional reference `UnitSystem` variants: `EMU`, `ESU`, `Gauss`, `LorentzHeaviside`, `SI2019`, `SI1976`, `CODATA`, `Conventional`, `International`, `InternationalMean`, `MetricEngineering`, `GravitationalMetric`, `IAU`, `IAUE`, `IAUJ`, `FPS`, `IPS`, `British`, `Survey`, `Hubble`, `Cosmological`, `CosmologicalQuantum`, `Meridian`, `Nautical`, `MPH`, `KKH`, `MTS`, `FFF`; and natural atomic units based on gravitational `coupling` and `finestructure` constant (`Planck`, `PlanckGauss`, `Stoney`, `Hartree`, `Rydberg`, `Schrodinger`, `Electronic`, `Natural`, `NaturalGauss`, `QCD`, `QCDGauss`, and `QCDoriginal`).
+Additional reference `UnitSystem` variants: `EMU`, `ESU`, `Gauss`, `LorentzHeaviside`, `SI2019`, `SI1976`, `CODATA`, `Conventional`, `International`, `InternationalMean`, `Engineering`, `Gravitational`, `IAU`, `IAUE`, `IAUJ`, `FPS`, `IPS`, `British`, `Survey`, `Hubble`, `Cosmological`, `CosmologicalQuantum`, `Meridian`, `Nautical`, `MPH`, `KKH`, `MTS`, `FFF`; and natural atomic units based on gravitational `coupling` and `finestructure` constant (`Planck`, `PlanckGauss`, `Stoney`, `Hartree`, `Rydberg`, `Schrodinger`, `Electronic`, `Natural`, `NaturalGauss`, `QCD`, `QCDGauss`, and `QCDoriginal`).
 
 Derived dimensions can be obtained from multiplicative base of 11 fundamental dimension symbols `F`, `M`, `L`, `T`, `Q`, `Θ`, `N`, `J`, `A`, `R`, `C` corresponding to `force`, `mass`, `length`, `time`, `charge`, `temperature`, `molaramount`, `luminousflux`, `angle`, `demagnetizingfactor`, and a `nonstandard` dimension.
 Specification of a `UnitSystem` is in dimensions of `entropy`, `angularmomentum`, `speed`, `permeability`, `mass`, `molarmass`, `luminousefficacy`, `angle`, `rationalization`, `lorentz`, `gravityforce`; whose `Constant` values are interpreted by units.
@@ -244,7 +244,7 @@ end
 
 Constructs new `UnitSystem` from `U` rescaled along `time`, `length`, `mass`, and `temperature` by the first four parameters. Additional optional parameters allow for customization of the `vacuumpermeability`, `molarmass`, and `gravity` constants.
 
-Examples of this type include `Nautical`, `Meridian`, `GravitationalMetric`, `MTS`, `KKH`, `MPH`, `IAU☉`, `IAUE`, `IAUJ`, `Hubble`, `Cosmological`, `CosmologicalQuantum`.
+Examples of this type include `Nautical`, `Meridian`, `Gravitational`, `MTS`, `KKH`, `MPH`, `IAU☉`, `IAUE`, `IAUJ`, `Hubble`, `Cosmological`, `CosmologicalQuantum`.
 However, most other constructors for `UnitSystem` derivations are based on internally calling `EntropySystem`, such as `AstronomicalSystem`, `ElectricSystem`, `GaussSystem`, and `RankineSystem`.
 This means `EntropySystem` also constructs the examples listed there.
 """
diff --git a/src/derived.jl b/src/derived.jl
index 1bc0a9b..f52b91f 100644
--- a/src/derived.jl
+++ b/src/derived.jl
@@ -107,7 +107,7 @@
 @pure ounce(U::UnitSystem) = mass(two(U)^-4,U,English)
 @pure slug(U::UnitSystem) = mass(one(U),U,British)
 @pure slinch(U::UnitSystem) = mass(one(U),U,IPS)
-@pure hyl(U::UnitSystem) = mass(one(U),U,GravitationalMetric)
+@pure hyl(U::UnitSystem) = mass(one(U),U,Gravitational)
 
 # force
 
@@ -115,7 +115,7 @@
 @pure newton(U::UnitSystem) = force(one(U),U,Metric)
 @pure poundal(U::UnitSystem) = force(one(U),U,FPS)
 @pure poundforce(U::UnitSystem) = force(one(U),U,English)
-@pure kilopond(U::UnitSystem) = force(one(U),U,MetricEngineering)
+@pure kilopond(U::UnitSystem) = force(one(U),U,Engineering)
 
 # pressure
 
@@ -151,7 +151,7 @@
 @pure thermalconductivity_water(U::UnitSystem) = thermalconductivity((two(U)^2*three(U)*five(U))^2/thermalunit(U),U,Metric)
 @pure horsepower(U::UnitSystem) = power(two(U)*five(U)^2*eleven(U),U,British)
 @pure horsepowerwatt(U::UnitSystem) = power(two(U)^4*three(U)^3/five(U)*normal(tau(U)),U,British)
-@pure horsepowermetric(U::UnitSystem) = power(three(U)*five(U)^2,U,GravitationalMetric)
+@pure horsepowermetric(U::UnitSystem) = power(three(U)*five(U)^2,U,Gravitational)
 @pure electricalhorsepower(U::UnitSystem) = power(Constant(746),U,Metric)
 
 # electromagnetic
diff --git a/src/derivedocs.jl b/src/derivedocs.jl
index e4c5a59..514adeb 100644
--- a/src/derivedocs.jl
+++ b/src/derivedocs.jl
@@ -171,8 +171,8 @@ $(unitext(:radian,"angle(𝟏,U,Metric)"))
 
 Unit of `angle` which is dimensionless (rad).
 ```Julia
-julia> radian(MetricEngineering) # rad
-$(radian(MetricEngineering))
+julia> radian(Engineering) # rad
+$(radian(Engineering))
 
 julia> radian(MetricDegree) # deg
 $(radian(MetricDegree))
@@ -193,8 +193,8 @@ $(unitext(:spatian,"angle(𝟏,U,MetricSpatian)"))
 
 Unit of `angle` which is dimensionless (rad).
 ```Julia
-julia> spatian(MetricEngineering) # rad
-$(spatian(MetricEngineering))
+julia> spatian(Engineering) # rad
+$(spatian(Engineering))
 
 julia> spatian(MetricDegree) # deg
 $(spatian(MetricDegree))
@@ -215,8 +215,8 @@ $(unitext(:degree,"angle(𝟏,U,MetricDegree)"))
 
 Unit of `angle` which divides a `turn` into `360` parts (rad).
 ```Julia
-julia> degree(MetricEngineering) # rad
-$(degree(MetricEngineering))
+julia> degree(Engineering) # rad
+$(degree(Engineering))
 
 julia> degree(MetricDegree) # deg
 $(degree(MetricDegree))
@@ -237,8 +237,8 @@ $(unitext(:gradian,"angle(𝟏,U,MetricGradian)"))
 
 Unit of `angle` which divides a `turn` into `400` parts (rad).
 ```Julia
-julia> gradian(MetricEngineering) # rad
-$(gradian(MetricEngineering))
+julia> gradian(Engineering) # rad
+$(gradian(Engineering))
 
 julia> gradian(MetricDegree) # deg
 $(gradian(MetricDegree))
@@ -259,8 +259,8 @@ $(unitext(:bradian,"angle(τ/𝟐^8,U,Metric)"))
 
 Unit of `angle` which divides a `turn` into `𝟐^8` or `256` parts (rad).
 ```Julia
-julia> bradian(MetricEngineering) # rad
-$(bradian(MetricEngineering))
+julia> bradian(Engineering) # rad
+$(bradian(Engineering))
 
 julia> bradian(MetricDegree) # deg
 $(bradian(MetricDegree))
@@ -281,8 +281,8 @@ $(unitext(:arcminute,"angle(𝟏,U,MetricArcminute)"))
 
 Unit of `angle` which divides a `degree` into `60` parts (rad).
 ```Julia
-julia> arcminute(MetricEngineering) # rad
-$(arcminute(MetricEngineering))
+julia> arcminute(Engineering) # rad
+$(arcminute(Engineering))
 
 julia> arcminute(MetricDegree) # deg
 $(arcminute(MetricDegree))
@@ -303,8 +303,8 @@ $(unitext(:arcsecond,"angle(𝟏,U,MetricArcsecond)"))
 
 Unit of `angle` which divides a `arcminute` into `60` parts (rad).
 ```Julia
-julia> arcsecond(MetricEngineering) # rad
-$(arcsecond(MetricEngineering))
+julia> arcsecond(Engineering) # rad
+$(arcsecond(Engineering))
 
 julia> arcsecond(MetricDegree) # deg
 $(arcsecond(MetricDegree))
@@ -327,8 +327,8 @@ $(unitext(:steradian,"solidangle(𝟏,U,Metric)"))
 
 Unit of `solidangle` which is dimensionless (rad²).
 ```Julia
-julia> steradian(MetricEngineering) # rad²
-$(steradian(MetricEngineering))
+julia> steradian(Engineering) # rad²
+$(steradian(Engineering))
 
 julia> steradian(MetricDegree) # deg²
 $(steradian(MetricDegree))
@@ -349,8 +349,8 @@ $(unitext(:squaredegree,"solidangle(𝟏,U,MetricDegree)"))
 
 Unit of `solidangle` which is a `degree` squared (rad²).
 ```Julia
-julia> squaredegree(MetricEngineering) # rad²
-$(squaredegree(MetricEngineering))
+julia> squaredegree(Engineering) # rad²
+$(squaredegree(Engineering))
 
 julia> squaredegree(MetricDegree) # deg²
 $(squaredegree(MetricDegree))
@@ -1122,8 +1122,8 @@ $(gram(English))
 julia> gram(British) # slug
 $(gram(British))
 
-julia> gram(GravitationalMetric) # hyl
-$(gram(GravitationalMetric))
+julia> gram(Gravitational) # hyl
+$(gram(Gravitational))
 ```
 """ gram
 
@@ -1144,8 +1144,8 @@ $(earthgram(English))
 julia> earthgram(British) # slug
 $(earthgram(British))
 
-julia> earthgram(GravitationalMetric) # hyl
-$(earthgram(GravitationalMetric))
+julia> earthgram(Gravitational) # hyl
+$(earthgram(Gravitational))
 ```
 """ earthgram
 
@@ -1166,8 +1166,8 @@ $(kilogram(English))
 julia> kilogram(British) # slug
 $(kilogram(British))
 
-julia> kilogram(GravitationalMetric) # hyl
-$(kilogram(GravitationalMetric))
+julia> kilogram(Gravitational) # hyl
+$(kilogram(Gravitational))
 ```
 """ kilogram
 
@@ -1188,8 +1188,8 @@ $(tonne(English))
 julia> tonne(British) # slug
 $(tonne(British))
 
-julia> tonne(GravitationalMetric) # hyl
-$(tonne(GravitationalMetric))
+julia> tonne(Gravitational) # hyl
+$(tonne(Gravitational))
 ```
 """ tonne
 
@@ -1210,8 +1210,8 @@ $(ton(English))
 julia> ton(British) # slug
 $(ton(British))
 
-julia> ton(GravitationalMetric) # hyl
-$(ton(GravitationalMetric))
+julia> ton(Gravitational) # hyl
+$(ton(Gravitational))
 ```
 """ ton
 
@@ -1232,8 +1232,8 @@ $(pound(English))
 julia> pound(British) # slug
 $(pound(British))
 
-julia> pound(GravitationalMetric) # hyl
-$(pound(GravitationalMetric))
+julia> pound(Gravitational) # hyl
+$(pound(Gravitational))
 ```
 """ pound
 
@@ -1254,8 +1254,8 @@ $(ounce(English))
 julia> ounce(British) # slug
 $(ounce(British))
 
-julia> ounce(GravitationalMetric) # hyl
-$(ounce(GravitationalMetric))
+julia> ounce(Gravitational) # hyl
+$(ounce(Gravitational))
 ```
 """ ounce
 
@@ -1276,8 +1276,8 @@ $(slug(English))
 julia> slug(British) # slug
 $(slug(British))
 
-julia> slug(GravitationalMetric) # hyl
-$(slug(GravitationalMetric))
+julia> slug(Gravitational) # hyl
+$(slug(Gravitational))
 ```
 """ slug
 
@@ -1298,13 +1298,13 @@ $(slinch(English))
 julia> slinch(British) # slug
 $(slinch(British))
 
-julia> slinch(GravitationalMetric) # hyl
-$(slinch(GravitationalMetric))
+julia> slinch(Gravitational) # hyl
+$(slinch(Gravitational))
 ```
 """ slinch
 
 @doc """
-$(unitext(:hyl,"mass(𝟏,U,GravitationalMetric)"))
+$(unitext(:hyl,"mass(𝟏,U,Gravitational)"))
 
 Gravitational Metric `hyl` unit of `mass` (kg or lb).
 ```Julia
@@ -1320,8 +1320,8 @@ $(hyl(English))
 julia> hyl(British) # slug
 $(hyl(British))
 
-julia> hyl(GravitationalMetric) # hyl
-$(hyl(GravitationalMetric))
+julia> hyl(Gravitational) # hyl
+$(hyl(Gravitational))
 ```
 """ hyl
 
@@ -1344,8 +1344,8 @@ $(dyne(English))
 julia> dyne(FPS) # pdl
 $(dyne(FPS))
 
-julia> dyne(MetricEngineering) # kp
-$(dyne(MetricEngineering))
+julia> dyne(Engineering) # kp
+$(dyne(Engineering))
 ```
 """ dyne
 
@@ -1366,8 +1366,8 @@ $(newton(English))
 julia> newton(FPS) # pdl
 $(newton(FPS))
 
-julia> newton(MetricEngineering) # kp
-$(newton(MetricEngineering))
+julia> newton(Engineering) # kp
+$(newton(Engineering))
 ```
 """ newton
 
@@ -1388,13 +1388,13 @@ $(poundal(English))
 julia> poundal(FPS) # pdl
 $(poundal(FPS))
 
-julia> poundal(MetricEngineering) # kp
-$(poundal(MetricEngineering))
+julia> poundal(Engineering) # kp
+$(poundal(Engineering))
 ```
 """ poundal
 
 @doc """
-$(unitext(:kilopond,"force(𝟏,U,MetricEngineering)"))
+$(unitext(:kilopond,"force(𝟏,U,Engineering)"))
 
 Gravitational `kilopond` unit of `force` used in engineering systems (N or lb).
 ```Julia
@@ -1410,8 +1410,8 @@ $(kilopond(English))
 julia> kilopond(FPS) # pdl
 $(kilopond(FPS))
 
-julia> kilopond(MetricEngineering) # kp
-$(kilopond(MetricEngineering))
+julia> kilopond(Engineering) # kp
+$(kilopond(Engineering))
 ```
 """ kilopond
 
@@ -1432,8 +1432,8 @@ $(poundforce(English))
 julia> poundforce(FPS) # pdl
 $(poundforce(FPS))
 
-julia> poundforce(MetricEngineering) # kp
-$(poundforce(MetricEngineering))
+julia> poundforce(Engineering) # kp
+$(poundforce(Engineering))
 ```
 """ poundforce
 
@@ -1764,8 +1764,8 @@ $(watt(Metric))
 julia> watt(English) # lb⋅ft⋅s⁻¹
 $(watt(English))
 
-julia> watt(MetricEngineering) # kgf⋅m⋅s⁻¹
-$(watt(MetricEngineering))
+julia> watt(Engineering) # kgf⋅m⋅s⁻¹
+$(watt(Engineering))
 ```
 """ watt
 
@@ -1780,8 +1780,8 @@ $(tonsrefrigeration(British))
 julia> tonsrefrigeration(Metric) # W
 $(tonsrefrigeration(Metric))
 
-julia> tonsrefrigeration(MetricEngineering) # kgf⋅m⋅s⁻¹
-$(tonsrefrigeration(MetricEngineering))
+julia> tonsrefrigeration(Engineering) # kgf⋅m⋅s⁻¹
+$(tonsrefrigeration(Engineering))
 ```
 """ tonsrefrigeration
 
@@ -1796,8 +1796,8 @@ $(boilerhorsepower(British))
 julia> boilerhorsepower(Metric) # W
 $(boilerhorsepower(Metric))
 
-julia> boilerhorsepower(MetricEngineering) # kgf⋅m⋅s⁻¹
-$(boilerhorsepower(MetricEngineering))
+julia> boilerhorsepower(Engineering) # kgf⋅m⋅s⁻¹
+$(boilerhorsepower(Engineering))
 ```
 """ boilerhorsepower
 
@@ -1812,8 +1812,8 @@ $(horsepower(British))
 julia> horsepower(Metric) # W
 $(horsepower(Metric))
 
-julia> horsepower(MetricEngineering) # kgf⋅m⋅s⁻¹
-$(horsepower(MetricEngineering))
+julia> horsepower(Engineering) # kgf⋅m⋅s⁻¹
+$(horsepower(Engineering))
 ```
 """ horsepower, HP
 
@@ -1828,13 +1828,13 @@ $(horsepowerwatt(British))
 julia> horsepowerwatt(Metric) # W
 $(horsepowerwatt(Metric))
 
-julia> horsepowerwatt(MetricEngineering) # kgf⋅m⋅s⁻¹
-$(horsepowerwatt(MetricEngineering))
+julia> horsepowerwatt(Engineering) # kgf⋅m⋅s⁻¹
+$(horsepowerwatt(Engineering))
 ```
 """ horsepowerwatt
 
 @doc """
-$(unitext(:horsepowermetric,"power(𝟑*𝟓^2,U,GravitationalMetric)"))
+$(unitext(:horsepowermetric,"power(𝟑*𝟓^2,U,Gravitational)"))
 
 Unit of `power` derived from raising 75 kp by 1 m in 1  in 1 s.
 ```Julia
@@ -1844,8 +1844,8 @@ $(horsepowermetric(British))
 julia> horsepowermetric(Metric) # W
 $(horsepowermetric(Metric))
 
-julia> horsepowermetric(MetricEngineering) # kgf⋅m⋅s⁻¹
-$(horsepowermetric(MetricEngineering))
+julia> horsepowermetric(Engineering) # kgf⋅m⋅s⁻¹
+$(horsepowermetric(Engineering))
 ```
 """ horsepowermetric
 
@@ -1860,8 +1860,8 @@ $(electricalhorsepower(British))
 julia> electricalhorsepower(Metric) # W
 $(electricalhorsepower(Metric))
 
-julia> electricalhorsepower(MetricEngineering) # kgf⋅m⋅s⁻¹
-$(electricalhorsepower(MetricEngineering))
+julia> electricalhorsepower(Engineering) # kgf⋅m⋅s⁻¹
+$(electricalhorsepower(Engineering))
 ```
 """ electricalhorsepower
 
@@ -2598,8 +2598,8 @@ $(unitext(:candela,"luminousintensity(𝟏,U,Metric)"))
 
 Common unit of `luminousintensity` (cd).
 ```Julia
-julia> candela(MetricEngineering) # lm⋅rad⁻²
-$(candela(MetricEngineering))
+julia> candela(Engineering) # lm⋅rad⁻²
+$(candela(Engineering))
 
 julia> candela(MetricDegree) # lm⋅deg⁻²
 $(candela(MetricDegree))
@@ -2668,8 +2668,8 @@ $(unitext(:nit,"luminance(𝟏,U,Metric)"))
 
 Metric unit of `luminance` (lx⋅rad⁻²).
 ```Julia
-julia> nit(MetricEngineering) # nt
-$(nit(MetricEngineering))
+julia> nit(Engineering) # nt
+$(nit(Engineering))
 
 julia> nit(MetricDegree) # lm⋅m⁻²deg⁻²
 $(nit(MetricDegree))
@@ -2690,8 +2690,8 @@ $(unitext(:apostilb,"luminance(𝟐/turn(U),U,Metric)"))
 
 Metric unit of `luminance` (lx⋅rad⁻²).
 ```Julia
-julia> apostilb(MetricEngineering) # nt
-$(apostilb(MetricEngineering))
+julia> apostilb(Engineering) # nt
+$(apostilb(Engineering))
 
 julia> apostilb(MetricDegree) # lm⋅m⁻²deg⁻²
 $(apostilb(MetricDegree))
@@ -2712,8 +2712,8 @@ $(unitext(:stilb,"luminance(𝟏,U,Gauss)"))
 
 Historic unit of `luminance` (lx⋅rad⁻²).
 ```Julia
-julia> stilb(MetricEngineering) # nt
-$(stilb(MetricEngineering))
+julia> stilb(Engineering) # nt
+$(stilb(Engineering))
 
 julia> stilb(MetricDegree) # lm⋅m⁻²deg⁻²
 $(stilb(MetricDegree))
@@ -2734,8 +2734,8 @@ $(unitext(:lambert,"luminance(𝟐/turn(U),U,Gauss)"))
 
 Historic unit of `luminance` (nt).
 ```Julia
-julia> lambert(MetricEngineering) # nt
-$(lambert(MetricEngineering))
+julia> lambert(Engineering) # nt
+$(lambert(Engineering))
 
 julia> lambert(MetricDegree) # lm⋅m⁻²deg⁻²
 $(lambert(MetricDegree))
@@ -2756,8 +2756,8 @@ $(unitext(:footlambert,"luminance(𝟐/turn(U),U,English)"))
 
 English unit of `luminance` (nt).
 ```Julia
-julia> footlambert(MetricEngineering) # nt
-$(footlambert(MetricEngineering))
+julia> footlambert(Engineering) # nt
+$(footlambert(Engineering))
 
 julia> footlambert(MetricDegree) # lm⋅m⁻²deg⁻²
 $(footlambert(MetricDegree))
@@ -2778,8 +2778,8 @@ $(unitext(:bril,"centi*nano*lambert(U)"))
 
 Reference unit of `luminance` (nt).
 ```Julia
-julia> bril(MetricEngineering) # nt
-$(bril(MetricEngineering))
+julia> bril(Engineering) # nt
+$(bril(Engineering))
 
 julia> bril(MetricDegree) # lm⋅m⁻²deg⁻²
 $(bril(MetricDegree))
@@ -2822,8 +2822,8 @@ $(unitext(:hertz,"𝟏/second(U)"))
 
 Metric unit of `frequency` (s⁻¹).
 ```Julia
-julia> hertz(MetricEngineering) # rad⋅s⁻¹
-$(hertz(MetricEngineering))
+julia> hertz(Engineering) # rad⋅s⁻¹
+$(hertz(Engineering))
 
 julia> hertz(IAU) # D⁻¹
 $(hertz(IAU))
@@ -2851,8 +2851,8 @@ $(unitext(:rpm,"turn(U)/minute(U)"))
 
 Revolutions per minute `rpm` unit of `angularfrequency` (rad⋅s⁻¹).
 ```Julia
-julia> rpm(MetricEngineering) # rad⋅s⁻¹
-$(rpm(MetricEngineering))
+julia> rpm(Engineering) # rad⋅s⁻¹
+$(rpm(Engineering))
 
 julia> rpm(MetricGradian) # gon⋅s⁻¹
 $(rpm(MetricGradian))
diff --git a/src/initdata.jl b/src/initdata.jl
index 8d80739..a624d0a 100644
--- a/src/initdata.jl
+++ b/src/initdata.jl
@@ -29,6 +29,9 @@ const tcq,em,mi = lcq*sqrt(mcq/sqrt(sqrt(ρΛ*(𝘤*ħ)^3))),sqrt(GME/g₀)*τ/
 
 @pure sackurtetrode(U::UnitSystem,P=atmosphere(U),T=kelvin(U),m=dalton(U)) = normal(log((Constant(exp(5/2))*boltzmann(U)*sqrt(boltzmann(U)/gravity(U)/turn(U)/planckreduced(U)^2)^3)*(T/P*sqrt(m*T)^3)))
 
+derived(U) = [x=>eval(:($x($U))) for x ∈ deleteat!(collect(UnitSystems.Derived),1)]
+constants(U) = [x=>eval(:($x($U))) for x ∈ (:hyperfine,UnitSystems.Constants...,UnitSystems.Physics...,:loschmidt,:mechanicalheat,:wienwavelength,:wienfrequency,:sackurtetrode,:eddington,:solarmass,:jupitermass,:earthmass,:gforce,:earthradius,:greatcircle,:nauticalmile,:hubble,:cosmological)]
+
 const Universe = Coupling(αG,α,μₑᵤ,μₚᵤ,ΩΛ)
 
 function unitsystem(kB,ħ,𝘤,μ₀,mₑ,Mᵤ=𝟏,Kcd=𝟏,θ=𝟏,λ=𝟏,αL=𝟏,g=𝟏,C=Universe,τ=τ,x=𝟐,y=𝟑,z=𝟓,w=𝟕,u=𝟏𝟏,v=𝟏𝟗,q=𝟒𝟑)
@@ -51,7 +54,7 @@ Constructs new `UnitSystem` from `molarmass` constant, `vacuumpermeability`, `mo
 UnitSystem(Ru*me/Mu/μₑᵤ/g0,h/τ/g0/θ,𝘤,μ0,me,Mu,Kcd*(mₑ/me)^2*(h/𝘩)*g0,θ,𝟏,𝟏,g0)
 ```
 
-Examples include `SI2019`, `SI1976`, `Metric`, `MetricEngineering`, `MetricTurn`, `MetricSpatian`, `MetricGradian`, `MetricDegree`, `MetricArcminute`, `MetricArcsecond`. In addition, the `ConventionalSystem` constructor further builds on `MetricSystem`, resulting in variations.
+Examples include `SI2019`, `SI1976`, `Metric`, `Engineering`, `MetricTurn`, `MetricSpatian`, `MetricGradian`, `MetricDegree`, `MetricArcminute`, `MetricArcsecond`. In addition, the `ConventionalSystem` constructor further builds on `MetricSystem`, resulting in variations.
 
 Other derived `UnitSystem` instances such as `British` or `English` or `IAU` are derived from an existing `Metric` specification generated by `MetricSystem`. The constructor `MetricSystem` incorporates several standard common numerical values and exposes variable arguments which can be substituted for customization, yielding the capability to generate historical variations having a common `Universe`.
 Derivative constructors are `EntropySystem`, `ElectricSystem`, `GaussSystem`, `RankineSystem`, and `AstronomicalSystem`.
@@ -85,7 +88,7 @@ RankineSystem(u,l,m,g0=𝟏) = EntropySystem(u,𝟏,l,m,°R,UnitSystems.vacuumpe
 const SI2019 = Quantity(MetricSystem())
 const Metric = Quantity(MetricSystem(milli,τ/𝟐^6/𝟓^7))
 #const SI2019Engineering = Quantity(MetricSystem(Mᵤ,μ₀/g₀,Rᵤ,g₀))
-const MetricEngineering = Quantity(MetricSystem(milli,τ/𝟐^6/𝟓^7/g₀,Rᵤ,g₀))
+const Engineering = Quantity(MetricSystem(milli,τ/𝟐^6/𝟓^7/g₀,Rᵤ,g₀))
 const MetricTurn = Quantity(MetricSystem(milli,τ/𝟐^6/𝟓^7,Rᵤ,𝟏,𝟏/τ))
 const MetricSpatian = Quantity(MetricSystem(milli,τ/𝟐^6/𝟓^7,Rᵤ,𝟏,𝟏/ς))
 const MetricGradian = Quantity(MetricSystem(milli,τ/𝟐^6/𝟓^7,Rᵤ,𝟏,𝟐^4*𝟓^2/τ))
@@ -127,7 +130,7 @@ const Nautical = Quantity(EntropySystem(Metric,HOUR,nm,em^3,𝟏,τ*𝟑^3/𝟐^
 const Meridian = Quantity(EntropySystem(Metric,𝟏,em,em^3,𝟏,τ/𝟐^6/𝟓^7,milli))
 #const MeridianEngineering = Quantity(EntropySystem(Metric,𝟏,em,em^3,𝟏,τ/𝟐^6/𝟓^7*em/g₀,milli,g₀/em))
 #const GravitationalSI2019 = Quantity(EntropySystem(SI2019,𝟏,𝟏,g₀))
-const GravitationalMetric = Quantity(EntropySystem(Metric,𝟏,𝟏,g₀))
+const Gravitational = Quantity(EntropySystem(Metric,𝟏,𝟏,g₀))
 #const GravitationalMeridian = Quantity(EntropySystem(Metric,𝟏,em,g₀*em^2,𝟏,τ/𝟐^6/𝟓^7*em/g₀,milli))
 const IAU☉ = Quantity(EntropySystem(Metric,DAY,au,GM☉/G))
 const IAUE = Quantity(EntropySystem(Metric,DAY,LD,GME/G))
@@ -152,6 +155,7 @@ const QCD = Quantity(unitsystem(𝟏,𝟏,𝟏,𝟏,inv(μₚₑ)))
 const QCDGauss = Quantity(unitsystem(𝟏,𝟏,𝟏,𝟐*τ,inv(μₚₑ)))
 const QCDoriginal = Quantity(unitsystem(𝟏,𝟏,𝟏,𝟐*τ*α,inv(μₚₑ)))
 
+const MetricEngineering, GravitationalMetric = Engineering, Gravitational
 export SI, MKS, ME, GM, CGS, CGS2019, CGSm, CGSe, HLU, FFF, AE, EE, BG # SIE, GSI, GSI2019
 export EnglishEngineering, BritishGravitational, AbsoluteEnglish, EnglishUS, EE2019, IAU
 #const SIE, GSI2019, GSI = SI2019Engineering, GravitationalSI2019, GravitationalSI2019
diff --git a/src/kinematicdocs.jl b/src/kinematicdocs.jl
index 51d3c30..ca5d826 100644
--- a/src/kinematicdocs.jl
+++ b/src/kinematicdocs.jl
@@ -540,8 +540,8 @@ $(force(English,Metric))
 julia> force(FPS,Metric) # pdl⋅N⁻¹
 $(force(FPS,Metric))
 
-julia> force(MetricEngineering,Metric) # kp⋅N⁻¹
-$(force(MetricEngineering,Metric))
+julia> force(Engineering,Metric) # kp⋅N⁻¹
+$(force(Engineering,Metric))
 ```
 """ force, F
 
@@ -553,8 +553,8 @@ Weight or `force` per `mass` or `gforce` (N/kg, m⋅s⁻²), unit conversion fac
 julia> specificforce(CGS,Metric)
 $(specificforce(CGS,Metric))
 
-julia> specificforce(MetricEngineering,Metric)
-$(specificforce(MetricEngineering,Metric))
+julia> specificforce(Engineering,Metric)
+$(specificforce(Engineering,Metric))
 
 julia> specificforce(English,Metric)
 $(specificforce(English,Metric))
@@ -569,8 +569,8 @@ Reference `acceleration` per `specificforce` (𝟏, F⁻¹MLT⁻²), unit conver
 julia> gravityforce(Metric,CGS)
 $(gravityforce(Metric,CGS))
 
-julia> gravityforce(Metric,MetricEngineering)
-$(gravityforce(Metric,MetricEngineering))
+julia> gravityforce(Metric,Engineering)
+$(gravityforce(Metric,Engineering))
 
 julia> gravityforce(Metric,English)
 $(gravityforce(Metric,English))
diff --git a/src/physicsdocs.jl b/src/physicsdocs.jl
index f0b9714..54eb126 100644
--- a/src/physicsdocs.jl
+++ b/src/physicsdocs.jl
@@ -43,8 +43,8 @@ $(unitext(:turn,"2π/angle(U)"))
 
 Complete rotation `angle` of revolution from a full circle.
 ```Julia
-julia> turn(MetricEngineering) # rad
-$(turn(MetricEngineering))
+julia> turn(Engineering) # rad
+$(turn(Engineering))
 
 julia> turn(MetricDegree) # deg
 $(turn(MetricDegree))
@@ -65,8 +65,8 @@ $(unitext(:spat,"4π/solidangle(U)"))
 
 Complete spherical `solidangle` around point from a full sphere.
 ```Julia
-julia> spat(MetricEngineering) # rad²
-$(spat(MetricEngineering))
+julia> spat(Engineering) # rad²
+$(spat(Engineering))
 
 julia> spat(MetricDegree) # deg²
 $(spat(MetricDegree))
@@ -480,8 +480,8 @@ Gravitational force reference used in technical engineering units (kg⋅m⋅N⁻
 julia> gravity(Metric)
 $(gravity(Metric))
 
-julia> gravity(MetricEngineering) # m⋅kg⋅N⁻¹⋅s⁻²
-$(gravity(MetricEngineering))
+julia> gravity(Engineering) # m⋅kg⋅N⁻¹⋅s⁻²
+$(gravity(Engineering))
 
 julia> gravity(English) # ft⋅lbm⋅lbf⁻¹⋅s⁻²
 $(gravity(English))
@@ -1338,8 +1338,8 @@ $(unitext(:gaussgravitation,"sqrt(gravitation(U)*solarmass(U)/astronomicalunit(U
 
 Gaussian  gravitational constant `k` of Newton's laws (Hz or rad⋅D⁻¹).
 ```Julia
-julia> gaussgravitation(MetricEngineering)
-$(gaussgravitation(MetricEngineering))
+julia> gaussgravitation(Engineering)
+$(gaussgravitation(Engineering))
 
 julia> gaussgravitation(MetricGradian)
 $(gaussgravitation(MetricGradian))
diff --git a/src/systems.jl b/src/systems.jl
index 4620783..1ae9541 100644
--- a/src/systems.jl
+++ b/src/systems.jl
@@ -288,36 +288,36 @@ $(luminousefficacy(MetricGradian))
 """ MetricGradian
 
 @doc """
-$(systext(:MetricEngineering,"MetricSystem(milli,𝟐*τ/𝟏𝟎^7,Rᵤ,g₀)"))
+$(systext(:Engineering,"MetricSystem(milli,𝟐*τ/𝟏𝟎^7,Rᵤ,g₀)"))
 
-Standard `MetricEngineering` system based on kilogram and kilopond (kilogram-force) units.
+Standard Metric `Engineering` system based on kilogram and kilopond (kilogram-force) units.
 
 ```Julia
-julia> boltzmann(MetricEngineering) # kgf⋅m⋅K⁻¹
-$(boltzmann(MetricEngineering))
+julia> boltzmann(Engineering) # kgf⋅m⋅K⁻¹
+$(boltzmann(Engineering))
 
-julia> planckreduced(MetricEngineering) # kgf⋅m⋅s⋅rad⁻¹
-$(planckreduced(MetricEngineering))
+julia> planckreduced(Engineering) # kgf⋅m⋅s⋅rad⁻¹
+$(planckreduced(Engineering))
 
-julia> lightspeed(MetricEngineering) # m⋅s⁻¹
-$(lightspeed(MetricEngineering))
+julia> lightspeed(Engineering) # m⋅s⁻¹
+$(lightspeed(Engineering))
 
-julia> vacuumpermeability(MetricEngineering) # kgf⋅s²⋅C⁻²
-$(vacuumpermeability(MetricEngineering))
+julia> vacuumpermeability(Engineering) # kgf⋅s²⋅C⁻²
+$(vacuumpermeability(Engineering))
 
-julia> electronmass(MetricEngineering) # kg
-$(electronmass(MetricEngineering))
+julia> electronmass(Engineering) # kg
+$(electronmass(Engineering))
 
-julia> molarmass(MetricEngineering) # kg⋅mol⁻¹
-$(molarmass(MetricEngineering))
+julia> molarmass(Engineering) # kg⋅mol⁻¹
+$(molarmass(Engineering))
 
-julia> luminousefficacy(MetricEngineering) # lm⋅s⋅m⁻¹⋅kgf⁻¹
-$(luminousefficacy(MetricEngineering))
+julia> luminousefficacy(Engineering) # lm⋅s⋅m⁻¹⋅kgf⁻¹
+$(luminousefficacy(Engineering))
 
-julia> gravity(MetricEngineering) # kg⋅m⋅kgf⁻¹⋅s⁻²
-$(gravity(MetricEngineering))
+julia> gravity(Engineering) # kg⋅m⋅kgf⁻¹⋅s⁻²
+$(gravity(Engineering))
 ```
-""" MetricEngineering, ME
+""" Engineering, ME
 
 #=@doc """
 $(systext(:SI2019Engineering,"MetricSystem(Mᵤ,μ₀,Rᵤ,g₀)"))
@@ -553,7 +553,7 @@ $(luminousefficacy(Meridian))
 """ Meridian
 
 #=@doc """
-$(systext(:MeridianEngineering,"EntropySystem(MetricEngineering,𝟏,em,em^3,𝟏,τ/𝟐^6/𝟓^7/g₀^2,milli)"))
+$(systext(:MeridianEngineering,"EntropySystem(Engineering,𝟏,em,em^3,𝟏,τ/𝟐^6/𝟓^7/g₀^2,milli)"))
 
 Modern ideal engineering `UnitSystem` variant of the original French `Meridian` system.
 
@@ -773,33 +773,33 @@ $(rationalization(Kennelly))
 """ Kennelly=#
 
 @doc """
-$(systext(:GravitationalMetric,"EntropySystem(Metric,𝟏,𝟏,g₀)"))
+$(systext(:Gravitational,"EntropySystem(Metric,𝟏,𝟏,g₀)"))
 
-Standard `GravitationalMetric` system based on `hyl` and `kilopond` units.
+Standard `Gravitational` system based on `hyl` and `kilopond` units.
 
 ```Julia
-julia> boltzmann(GravitationalMetric) # kgf⋅m⋅K⁻¹
-$(boltzmann(GravitationalMetric))
+julia> boltzmann(Gravitational) # kgf⋅m⋅K⁻¹
+$(boltzmann(Gravitational))
 
-julia> planckreduced(GravitationalMetric) # kgf⋅m⋅s⋅rad⁻¹
-$(planckreduced(GravitationalMetric))
+julia> planckreduced(Gravitational) # kgf⋅m⋅s⋅rad⁻¹
+$(planckreduced(Gravitational))
 
-julia> lightspeed(GravitationalMetric) # m⋅s⁻¹
-$(lightspeed(GravitationalMetric))
+julia> lightspeed(Gravitational) # m⋅s⁻¹
+$(lightspeed(Gravitational))
 
-julia> vacuumpermeability(GravitationalMetric) # H⋅m⁻¹
-$(vacuumpermeability(GravitationalMetric))
+julia> vacuumpermeability(Gravitational) # H⋅m⁻¹
+$(vacuumpermeability(Gravitational))
 
-julia> electronmass(GravitationalMetric) # hyl
-$(electronmass(GravitationalMetric))
+julia> electronmass(Gravitational) # hyl
+$(electronmass(Gravitational))
 
-julia> molarmass(GravitationalMetric) # hyl⋅mol⁻¹
-$(molarmass(GravitationalMetric))
+julia> molarmass(Gravitational) # hyl⋅mol⁻¹
+$(molarmass(Gravitational))
 
-julia> luminousefficacy(GravitationalMetric) # lm⋅s⋅m⁻¹⋅kgf⁻¹
-$(luminousefficacy(GravitationalMetric))
+julia> luminousefficacy(Gravitational) # lm⋅s⋅m⁻¹⋅kgf⁻¹
+$(luminousefficacy(Gravitational))
 ```
-""" GravitationalMetric, GM
+""" Gravitational, GM
 
 #=@doc """
 $(systext(:GraviationalSI2019,"EntropySystem(SI2019,𝟏,𝟏,g₀)"))
@@ -825,8 +825,8 @@ $(electronmass(GravitationalSI2019))
 julia> molarmass(GravitationalSI2019) # hyl⋅mol⁻¹
 $(molarmass(GravitationalSI2019))
 
-julia> luminousefficacy(GravitationalMetric) # lm⋅s⋅m⁻¹⋅kgf⁻¹
-$(luminousefficacy(GravitationalMetric))
+julia> luminousefficacy(Gravitational) # lm⋅s⋅m⁻¹⋅kgf⁻¹
+$(luminousefficacy(Gravitational))
 ```
 """ GravitationalSI2019, GSI, GSI2019=#