**E`qui*lat"er*al** (?), a. [L. *aequilateralis*; *aequus* equal + *latus*, *lateris*, side: cf. F. *'equilat'eral*.]

Having all the sides equal; as, an **equilateral** triangle; an **equilateral** polygon.

Equilateral hyperbola Geom., one whose axes are equal. -- Equilateral shell Zool., one in which a transverse line drawn through the apex of the umbo bisects the valve, or divides it into two equal and symmetrical parts. -- Mutually equilateral, applied to two figures, when every side of the one has its equal among the sides of the other.

© Webster 1913.

**E`qui*lat"er*al**, n.

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

© Webster 1913.