Origin of principal diagonal
Definition for principal diagonal (2 of 2)
- connecting two nonadjacent angles or vertices of a polygon or polyhedron, as a straight line.
- extending from one edge of a solid figure to an opposite edge, as a plane.
Origin of diagonal
British Dictionary definitions for principal diagonal
Word Origin for diagonal
Word Origin and History for principal diagonal
1540s (implied in diagonally), from Middle French diagonal, from Latin diagonalis, from diagonus "slanting line," from Greek diagonios "from angle to angle," from dia- "across" (see dia-) + gonia "angle," related to gony "knee" (see knee (n.)). As a noun, from 1570s.