3.04 SI/metric units

Preferred spellings of terms have been established in National Standard of Canada CAN/CSA-Z234.1-89 for a number of SI/metric units and prefixes: deca (not deka), gram (not gramme), litre (not liter) and tonne or metric ton (not metric tonne).

In two cases the final vowel of a unit prefix is omitted: megohm and kilohm. In other cases where the unit name begins with a vowel, both vowels are retained.

Note that meter is the spelling for a measuring device, while metre is the unit of length.

Note also that the singular and plural of the following unit names are identical: hertz, lux and siemens.

© Services publics et Approvisionnement Canada, 2025
TERMIUM Plus^®, el banco de datos terminológicos y lingüísticos del Gobierno de Canadá
Ayuda a la redacción – The Canadian Style
Un producto de la Oficina de Traducciones