Where does “diagonal” come from?

Diagonal comes from Middle French diagonal, from Latin diagonalis, from Ancient Greek διαγώνιος, combining διά (dia, through) and γώνιος (gōnios, angle), ultimately from Proto-Indo-European roots meaning two.

diagonal (English): Joining two nonadjacent vertices; Having slanted...

Definitions

  1. Joining two nonadjacent vertices; Having slanted...

Ancestry of “diagonal”, step by step

StepLanguageWordMeaning
1Middle Frenchdiagonal—
2Latindiagōnālisdiagonal
3Ancient Greekδιαγώνιοςfrom angle to angle
4Ancient Greekδῐᾰ-apart; through, across; through; in different...
5Ancient Greekδιάthroughout
6Proto-Indo-Europeandwístwice, doubly; in two
7Proto-Indo-Europeandwóh₁two

Words derived from “diagonal”

Every word from Proto-Indo-European dwóh₁ →Every word from Ancient Greek δῐᾰ- →Every word from Proto-Indo-European dwís →