Why don't we call an equilateral triangle an isosceles triangle?

Why does the perpendicular bisector of a side of a triangle only pass through the opposite vertex if the triangles is isosceles or equilateral? - Quora

How to determine if a triangle is scalene, isosceles or equilateral by only knowing its side lengths - Quora

Proofs concerning equilateral triangles (video)

Isosceles and Equilateral Triangles

The University of Tokyo on LinkedIn: Why don't we call an equilateral triangle an isosceles triangle?

Focus The University of Tokyo

Why do isosceles triangles have two equal angles? - Quora

Isosceles and Equilateral Triangles

Focus The University of Tokyo