Definition of "equilateral"

(geometry, of a polygon) Having all the sides equal.  examples

(geometry, of a polyhedron) Having all the faces equal.  examples

(zoology) Having the two sides equal, as a surface divisible by a longitudinal median line into two halves of the same form.

(zoology) Having all the convolutions of the shell in one plane, chiefly of foraminifers.

A side exactly corresponding, or equal, to others.  examples

A figure having all its sides equal.  examples