isosceles

The story

1. Ancient Greek · derived fromἰσοσκελής“equal-legged”
2. Latin · borrowed fromīsoscelēs
3. English todayisosceles

Borrowed from Latin īsoscelēs, from Ancient Greek ἰσοσκελής (isoskelḗs, “equal-legged”), from ἴσος (ísos, “equal”) + σκέλος (skélos, “leg”) + -ής (-ḗs, adjective suffix). See also iso-.