■ cardinal number ( plural forties )
1》 the number equivalent to the product of four and ten; ten less than fifty; 40. (Roman numeral: xl or XL .)
2》 ( the Forties ) the central North Sea between Scotland and southern Norway, so called from its prevailing depth of ~ fathoms or more.
Phrases
~ winks informal a short daytime sleep.
Derivatives
fortieth ordinal number .
~fold adjective & adverb
Origin
OE fēowertig (see four , -ty 2 ).