adj.
Pronunciation: ˌ ē -kw ə - ' la-t ə -r ə l, ˌ e-, - ' la-tr ə l
Function: adjective
Etymology: Late Latin aequilateralis, from Latin aequi- + later-, latus side ― more at LATERAL
Date: 1570
1 : having all sides equal <an equilateral triangle> <an equilateral polygon> ― see TRIANGLE illustration
2 : having all the faces equal <an equilateral polyhedron>