In geometry, a **square** is a regular quadrilateral. This means that it has four equal sides and four equal angles (90-degree angles, or right angles). It can also be defined as a rectangle in which two adjacent sides have equal length. A square with vertices ABCD would be denoted *ABCD*.

The square is the n=2 case of the families of n-hypercubes and n-orthoplexes.

Read more about Square: Characterizations, Perimeter and Area, Coordinates and Equations, Construction, Properties, Other Facts, Non-Euclidean Geometry, Graphs

### Famous quotes containing the word square:

“After the planet becomes theirs, many millions of years will have to pass before a beetle particularly loved by God, at the end of its calculations will find written on a sheet of paper in letters of fire that energy is equal to the mass multiplied by the *square* of the velocity of light. The new kings of the world will live tranquilly for a long time, confining themselves to devouring each other and being parasites among each other on a cottage industry scale.”

—Primo Levi (1919–1987)

“Interpreting the dance: young women in white dancing in a ring can only be virgins; old women in black dancing in a ring can only be witches; but middle-aged women in colors, *square* dancing...?”

—Mason Cooley (b. 1927)

“Houses haunt me.

That last house!

How it sat like a *square* box!”

—Anne Sexton (1928–1974)