equilateral, a. [L. aequilateralis; aequus equal + latus, lateris, side: cf. F. équilatéral.].
Equilateral hyperbola (Geom.), one whose axes are equal. -- Equilateral shell (Zoöl.), 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.
Having all the sides equal; as, an equilateral triangle; an equilateral polygon. [1913 Webster]
A side exactly corresponding, or equal, to others; also, a figure of equal sides. [1913 Webster]
balanced, coequal, coordinate, equal, equiangular, equidimensional, equiproportional, equisided, equisized, equispaced, eurythmic, even, finished, harmonious, isometric, proportioned, regular, symmetric, uniform, well-balanced, well-set, well-set-up