migrate to math ed se if need be please. i'm lazy =)
A circle is an ellipse with equal foci. A square is a rectangle with equal sides. Why is there no special name for equilateral triangle?
Context is
kindergartners find confusing that any square is a rectangle (or here)
people develop misconception in kindergarten that squares are not rectangles
But why in the first place do we have special names for certain types of ellipses and rectangles but don't have special names for equilateral, isosceles or right triangles?
CMV: I think everyone's lives would be much easier if the words 'circle' and 'square' did not exist. To describe a rectangle with equal sides, we follow what we do with a triangle with equal sides:
For kindergartners or anyone who doesn't know the word 'equilateral', call them rectangles just as is done for triangles i.e. no distinction made between an equilateral triangle and a non-equilateral triangle
For people who know the word 'equilateral', replace 'square' with 'equilateral rectangle'
But I'm guessing there may be something to do with quadrilaterals since there are a lot of possible quadrilaterals relative to possible trilaterals