The decade of the 1840s, 1940s, etc. / The decade of one's life from age 40 through age 49. / (temperature, rates, plural only) The range between 40 and 49.

plural of forty

From or evoking the 41st through 50th years of a century (chiefly the 1940s).

A sea area, in the northern part of the North Sea, where the depth of water is consistently forty fathoms

(slang) A bottle of beer containing forty fluid ounces.

The cardinal number occurring after thirty-nine and before forty-one.

(phonetics) Strongly articulated (of a consonant), hence voiceless.

(phonetics) A fortis consonant.

A surname.

plural of Forti