The property of being four in number.

A four-wheel-drive vehicle with a four-speed transmission. / A four-wheel vehicle with four-wheel-drive. / By extension, any four-wheel-drive vehicle.

plural of four-by-four

A numerical value equal to 4; the number after three and before five; two plus two. This many dots (••••) / Describing a set or group with four elements.

(countable) The digit or figure 4; an occurrence thereof. / (countable) Anything measuring four units, as length. / A person who is four years old.

plural of four

(poker slang) A pair of fours. / (UK, prison slang) The cells located on the third floor.

Obsolete spelling of four

(slang, US) a naive or clueless person.

(music) A meter or rhythm with four beats to a measure and four beats to a whole note. Specifically simple quadruple time or common time.