A four-sided plane figure is a quadrilateral or quadrangle, sometimes also called a tetragon. It can be further classified as a rectangle or oblong, kite, rhombus, and square.

The meaning of FOUR is a number that is one more than three. How to use four in a sentence.

something representing, represented by, or consisting of four units, such as a playing card with four symbols on it

Idiom on all fours (Definition of four from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)

1. The cardinal number equal to 3 + 1. 2. The fourth in a set or sequence. 3. Something having four parts, units, or members, such as a musical quartet or a four-cylinder engine.

/fɔ/ IPA guide Other forms: fours Definitions of four noun the cardinal number that is the sum of three and one synonyms: 4, IV, Little Joe, foursome, quadruplet, quartet, quatern, quaternary, quaternion, …

Feb 23, 2026 · Describing a set or group with four elements. four (countable and uncountable, plural fours) (countable) The digit or figure 4; an occurrence thereof. (countable) Anything measuring four …

Four is the second square number (a "square number" is an integer that can be written as the square of some other integer) and the second centered triangular number.

WordReference Random House Learner's Dictionary of American English © 2025 four /fɔr/ n. [countable] a cardinal number, three plus one. a symbol for this number, as 4 or IV. adj. [before a …

Four is a cardinal number that represents the quantity or value of a group or collection consisting of three additional units. It is the number that follows three and precedes five in the numerical sequence.