Tonne

How to spell tonne

5 letters · 1 syllable

How to pronounce tonne

What does tonne mean?

1. nounA metric unit of mass equal to one thousand kilograms.

Tonne in a sentence

• The lorry was carrying nearly a tonne of gravel.

• Each tonne of recycled steel saves a measurable amount of energy.

Where does tonne come from?

Language of origin: French

The word comes directly from French tonne, the metric unit equal to one thousand kilograms, and it traces back to the Late Latin tunna, which meant a large cask or barrel for storing liquids. That cask sense is why the related English word 'tun' still names a big wine or beer barrel, and why the older weight word 'ton' originally referred to the heft of such a full barrel. The Latin tunna may itself have come from a Celtic source, so the line of descent is genuinely old and a little uncertain at its very root. English already had 'ton' for the customary weight, and when the metric system spread in the twentieth century writers adopted the French spelling 'tonne' to keep the metric thousand-kilogram unit visually distinct. That doubled-n French spelling is the whole point: it signals the metric measure and separates it from its homophone 'ton', which is exactly the trap, since the two sound identical.

How the word is built

• tonne (whole word borrowed from French; from Late Latin tunna, a large cask or barrel)

British and American spelling

Tonne is the British spelling. American English spells it ton.