n. & adj.
--n. (pl. -ies)
1. the product of four and ten.
2 a symbol for this (40, xl, XL).
3 (in pl.) the numbers from 40 to 49, esp. the years of a century or of a person's life.
4 (the Forties) Brit. the sea area between the NE coast of Scotland and the SW coast of Norway (so called from its depth of forty fathoms or more).
--adj. that amount to forty.
Phrases and idioms:
forty-first, -second , etc. the ordinal numbers between fortieth and fiftieth. forty-five a gramophone record played at 45 r.p.m. the Forty-five the Jacobite rebellion of 1745. forty-niner US a seeker for gold etc., esp. in the Californian gold-rush of 1849. forty-one, -two , etc. the cardinal numbers between forty and fifty. forty winks colloq. a short sleep.
Derivatives:
fortieth adj. & n. fortyfold adj. & adv.
Etymology: OE feowertig (as FOUR, -TY(2))