equilateral

adj. having equal sides

In geometry, an equilateral polygon is a polygon which has all sides of the same length. An equilateral polygon which is convex and cyclic (its vertices are on a circle) is a regular polygon.An equilateral triangle is a triangle of equal edge lengths. All equilateral triangles are similar to each other with 60 degree angles.
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Adjective
1. having all sides or faces equal
(similar) equal

adj. equilateral, having equal sides

n. equilateral

(n.)
A side exactly corresponding, or equal, to others; also, a figure of equal sides.
  

(a.)
Having all the sides equal; as, an equilateral triangle; an equilateral polygon.