adjective

- having all the sides equal: an equilateral triangle.

noun

- a figure having all its sides equal.
- a side equivalent, or equal, to others.

adjective

- having all sides of equal lengthan equilateral triangle

noun

- a geometric figure having all its sides of equal length
- a side that is equal in length to other sides

1560s, from Late Latin aequilateralis, from aequi- (see equal (adj.)) + lateralis (see lateral).

- Having all sides of equal length, as a triangle that is neither scalene nor isosceles.