- triangle (n.)
- late 14c., from Old French triangle (13c.), from Latin triangulum "triangle," from neuter of adj. triangulus "three-cornered," from tri- "three" (see tri-) + angulus "corner, angle" (see angle (n.)).
In the huts of witches all the instruments and implements are triangular. ["Handwörterbuch des deutschen Aberglaubens"]