English

equidiagonal

From equi- + diagonal.

Old Latin aiquos

Latin aequus ‘equal’

English equi-

Ancient Greek διαγώνιος ‘from angle to angle’

Latin diagōnālis

Middle French diagonal

Today it means

adj Of a convex quadrilateral: having the two diagonals of equal length.

Language periods are conventional ranges, not dates for this word.

Etymograph / equidiagonal