hypotenuse

/haɪˌpɑtnˈus/

Other forms: hypotenuses

The hypotenuse is the side of a right triangle that’s opposite the 90-degree angle. It’s a term specific to math, specifically geometry.

Hypotenuse comes from the Greek word hypoteinousa which means "stretching under." The hypotenuse “stretches under” the right angle of a triangle, which has an angle of 90 degrees. A right angle is the kind of angle that appears four times in squares and rectangles. If your triangle has a right angle, the line opposite that angle is the hypotenuse.

Definitions of hypotenuse

1. noun

   the side of a right triangle opposite the right angle
   type of:

   flank

   a subfigure consisting of a side of something