Diagonal
/daɪˈæɡ.ən.əl/noun
A straight line joining two non-adjacent corners of a polygon or polyhedron.
Did you know?The term 'diagonal' combines roots meaning 'to cross' and 'angle', linking geometry to ancient concepts of pathways and connections.
Etymological Timeline
Late Latin
Latin
diagonalis
“Crossing from one angle to another.”
Greek
Greek
diagonios
“From one corner to another.”
12th Century
Old French
diagonal
“Relating to angles that cross.”
16th Century
Middle English
diagonal
“Pertaining to a line connecting non-adjacent corners.”
Modern English
English
diagonal
“A line crossing from one vertex to another in geometry.”