Alphabetical index
pascal
Unit of measurement of pressure, symbol: Pa.
“per” or “divided by”
The symbol for “per” is /
e.g. 50 km/h not 50 kph.
peta
Prefix of multiple 1015, symbol: P.
pico
Prefix for a subdivision of 10-12, symbol: p.
plurals
Symbols are never pluralised.
e.g. 25 kg not 25 kgs.
precision
A number normally implies its precision; thus 14 m is likely to mean a distance between 13.5 m and 14.5 m. When converting, do not make the converted figure more precise than is implied in the original e.g. 20 000 feet becomes 6000 m not 6096 m.
prefixes
A prefix is a way of multiplying or dividing a unit by 10, 100, 1000, etc.
punctuation
Do not put a full stop (period) after a unit symbol, except at the end of a sentence.
Leave a space between the number and the unit where possible.
