Vapor

How to spell vapor

5 letters · 2 syllables

How to pronounce vapor

Say the part in capitals loudest.

What does vapor mean?

1. nounA substance suspended in the air as a fine mist or gas, especially water that has turned from liquid into airborne form.

Vapor in a sentence

• The kettle filled the kitchen with warm vapor as it boiled.

• Engineers measured how much fuel vapor collected inside the sealed tank.

Where does vapor come from?

Language of origin: Latin

The word comes straight from the Latin vapor, which meant 'steam', 'warmth', or a moist exhalation rising from a surface. Romans used it for the visible mist given off by hot water or warm ground, and the sense carried that idea of something rising and dispersing into the air. English borrowed it through Old French during the 1300s, originally spelled with the French-influenced -our ending that British writers still keep in 'vapour'. American spelling, shaped in part by Noah Webster's nineteenth-century reforms, trimmed the silent-leaning -our back toward the original Latin -or, giving 'vapor'. The same root survives in 'evaporate' and 'vaporise', which is a useful reminder that the core spelling is v-a-p-o-r before any ending is added.

How the word is built

• vapor (from Latin vapor: steam, warm exhalation); the American spelling drops the British -our ending in favour of -or

British and American spelling

Vapor is the American spelling. British English spells it vapour.