SI unit
1
3.8
- noun
- /ɛs aɪ ˈjunɪt/
- Specialized
:
unidad SI
- In brief: According to Wikipedia, "Lux" is "the SI unit of illuminance and luminous emittance, measuring luminous flux per unit area."
Examples
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Mega Grays are the Grays are the SI unit of dose, and dose is energy absorbed divided by mass.
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Since weight is a force, its SI unit is the newton.
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The usual symbol for mass is m, and its SI unit is the kilogram.
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The Kelvin is the SI unit for temperature.
Synonyms
3
3.2
A fixed amount used as a standard to measure length, weight, or volume
1
2.4
A unit of measurement used in the metric system, like a meter or kilogram
A standard amount used to measure things like length or weight
How Official
- Specialized
1
3.8
- Specialized
- Formal
175
2.8
- Informal
31
3.8
Surface Forms
Morphology
The meaning is directly and compositionally derived from 'SI' (the standardized system of measurement) combined with 'unit' (a measurement quantity), so the phrase denotes a unit belonging to that system. This straightforward noun–noun specification is cross-linguistically common and therefore comprehensible to a B1 learner who knows both constituents.
Etymology
SI unit comes from the letters SI, short for the French phrase 'Système international d'unités', which means an international set of ways to measure. So a SI unit is a unit, like the meter or the kelvin, that belongs to that international system and helps people make measurements the same everywhere.