for unit, quantity, base size, dimension, attachment
Length, extent, diameter, volume, mass, time, population, etc are called quantities.
Length, extent, diameter, etc are physical quantities.
The quantity is a feature that allows the numerical comparison of two equal sizes. A value can be assigned to any quantity.
The term quantity is defined in the DIN 1313: 198-12. Further information in Wikipedia: https://en.wikipedia.org/wiki/Physical_quantity
The term "characteristic" is defined in DIN 55350-12. The characteristic is a feature that can be associated with objective methods, such as measuring a value. The terms characteristic and size have a similar meaning. The postal code is, for example, a characteristic, but no size, because a size comparison or ratio formation of two postal codes does not make sense.
The value of a size is determined by a numerical value and a unit. Für viele Einheiten sind besondere Einheitenzeichen vereinbart in der DIN 1301. For many units there are special unit symbols, which are agreed in the DIN 1301.
Examples: The units of size "length" are among other meter (m), centimeters (cm). Units of quantity "mass" are e.g. kilogram (kg) or gram (G).
https://en.wikipedia.org/wiki/Units_of_measurement
The physical quantities "length" (L), thickness (t), route (s), extent (u) belong to the same dimension "length" with units of meters (m).
The dimension describes the qualitative characteristics of a physical quantity, the quantitative characteristics of a dimension are described with numerical value and unit.
The international SI unit system consists of 7 basic units meter (m), kilogram (kg), second (s), ampere (A), Kelvin (K), mole (mol) and candela (cd) and all the derived units.
The SI unit system is a coherent unit system, because all units may be derived from products of orders of magnitude of the base units.
| dimension | size symbol | dimension symbol | base unit | unit symbol |
|---|---|---|---|---|
| length | l | L | metre | m |
| mass | m | M | kilogram | kg |
| time | t | T |
second |
s |
| electric current | i | I | ampere | A |
| temperature | T | Θ | kelvin | K |
| amount of substance | n | N | mole | mol |
| luminous intensity | lv | J | candela | cd |
Resolutions (Resolutions unit, prefixes) are used to form many multiples or fractions of units, thereby avoiding numbers with pre- or decimal.
| symbol | name | power of ten | value | designation |
|---|---|---|---|---|
| G | Giga | 109 | 1.000.000.000 | billion |
| M | Mega | 106 | 1.000.000 | million |
| k | kilo | 103 | 1.000 | thousand |
| 100 | 1 | one | ||
| m | Milli | 10-3 | 0.001 | per thousand; per mil |
| µ | Mikro | 10-6 | 0.000001 | millionth; ppm |
| n | Nano | 10-9 | 0.000000001 | billionth |
