Question

equilateral On her desk she kept an equilateral prism, through which every morning the sun would project the colors of the spectrum onto the far wall. equilateral*

Accepted Answer

Having all sides or faces equal. Since equi- means “equal” (see EQU), the meaning of equilateral is easy to guess from its roots. The word is mostly used in geometry. The standard polygons (many-sided geometrical shapes)—the pentagon, hexagon, octagon, etc.—are assumed to be equilateral if we don't say otherwise; an equilateral rectangle has the special name square. But triangles are particularly important, and many triangles are not equal-sided. The standard polyhedrons (many-sided solids) are also equilateral. Most common is the cube, all of whose sides are square. The tetrahedron has four triangular sides and thus is a pyramid with a triangular base, unlike the pyramids of Egypt with their square bases.

word	equilateral
definition	Having all sides or faces equal.
eg_sentence	On her desk she kept an equilateral prism, through which every morning the sun would project the colors of the spectrum onto the far wall.
explanation	Since equi- means “equal” (see EQU), the meaning of equilateral is easy to guess from its roots. The word is mostly used in geometry. The standard polygons (many-sided geometrical shapes)—the pentagon, hexagon, octagon, etc.—are assumed to be equilateral if we don't say otherwise; an equilateral rectangle has the special name square. But triangles are particularly important, and many triangles are not equal-sided. The standard polyhedrons (many-sided solids) are also equilateral. Most common is the cube, all of whose sides are square. The tetrahedron has four triangular sides and thus is a pyramid with a triangular base, unlike the pyramids of Egypt with their square bases.
IPA	equilateral*

Equilateral Sides Standard Many Sided Square Triangles Triangular Faces