mm
mm — noun
1. written abbreviation for millimetre — a unit for measuring short lengths or smal
written abbreviation for millimetre — a unit for measuring short lengths or small distances, equal to one thousandth of a metre.
The rainfall measured only 2 mm overnight, so the garden is still dry.
number + mm measuring natural quantity (rainfall)
Selim cut a 15 mm strip of wood for the shelf he was building.
number + mm as attributive adjective before noun
The screw has a diameter of 6 mm and needs a matching nut.
Tamar checked the tyre tread depth and found it was only 4 mm.
A standard SD card is 32 mm long and 24 mm wide.
- millimetre
the full written form; 'mm' is the standard abbreviation used in measurements
文法句型
number + mm + (long/wide/thick/deep)
number + mm
用法筆記
Used identically in British English (millimetre) and American English (millimeter). The space between the number and 'mm' is optional in informal writing but recommended in formal and technical contexts.
常見錯誤
2. mm is short for millimolar — a unit used mainly in chemistry to show how concent
mm is short for millimolar — a unit used mainly in chemistry to show how concentrated a solution is. One millimolar equals one thousandth of a mole of a substance in each litre of liquid.
Quinn prepared a 5 mm solution of sodium chloride for the experiment.
number + mm + solution + of + substance (concentration pattern)
The lab report stated that the calcium level was 2.5 mm.
number + mm used alone, referring to concentration
Imran diluted the stock solution to a final concentration of 10 mm.
A 1 mm glucose solution was used to test the enzyme reaction.
Before the titration, the team adjusted the buffer concentration to 50 mm.
文法句型
number + mm + of + substance
number + mm
用法筆記
Almost exclusively used in written lab work and scientific publications. In spoken chemistry, the full word 'millimolar' is preferred.