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
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 units, as length. Do you have any more fours? I want to make this a little taller.
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.
In mathematics, the number four is an even number and the smallest composite number. Four is also the second square number after one. A small minority of people have four fingers on each hand and four toes on each foot. [source?] Four squared is 16, and four doubled is 8.