Unit of measurement

A unit of measurement was a definite magnitude (amount) of a quantity (physical property) used as a standard of measurement.
== Systems of units ==
A system of measurement was a collection of units of measurement and rules relating them to each other.
=== Standard galactic units ===
Standard galactic or SG units were a system of units that served as a galactic standard due to wild variation between star systems. The system included measurements of time, such as the day and year, as well as other standard units.
=== Basic units ===
Basic units were a system of units that were defined in terms of universal physical constants.
=== Variable units ===
Variable units were a collection of units that varied between star system, but could not be standardised. This included units such as weeks and months, which were dependent on calendars. This also included subsystems of 'traditional units', based around physical anatomy, such as the cubit.
=== Other ===
* Metric units
* Imperial units
== Units ==
=== Spatial ===
==== Length ====
System 	Unit 	Symbol 	Multiples
SG units 	Metre 	m 	Centimetre, kilometre, etc.
Basic units	Astronomical unit	au 	
Basic units	Light-year 	ly 	Light-second, light-minute, light-hour, light-day
Basic units	Parsec 	pc 	Kiloparsec, megaparsec, gigaparsec
Basic units	Planck length 	𝓁P 	
Imperial 	Inch 	in or ″ 	
Imperial 	Foot 	ft or ′ 	
Imperial 	Yard 	yd 	
Imperial 	Mile 	mi 	
Other 	Fathom 	fathom 	
Other 	Nautical mile 	M, NM, or nmi	
==== Area ====
For every unit of length, there is a corresponding unit of area, namely the area of a square with the given side length.
* SG units
** Square metre and multiples (square centimetre, square kilometre, etc.)
* Other
** Imperial
*** Square inch
*** Square foot
*** Square yard
*** Square mile
==== Volume ====
* SG units
** Cubic metre and multiples (cubic centimetre, cubic kilometre, etc.)
** Litre
* Other
** Imperial
*** Cubic inch
*** Cubic foot
*** Cubic yard
*** Gallon
*** Pint
=== Temporal ===
==== Time ====
* SG units
** Standard galactic second and multiples (millisecond, microsecond, etc.)
** Standard galactic minute
** Standard galactic hour
** Standard galactic day
** Standard galactic year and multiples (decade, century, etc.)
* Variable units
** Week (and fortnight)
** Month
* Basic units
** Planck time
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