Meaning

noun a Greek sandwich: sliced roast lamb with onion and tomato stuffed into pita bread

noun rotating mechanism in the form of a universally mounted spinning wheel that offers resistance to turns in any direction

originBack-formation from the plural gyros, from Greek γύρος (gýros); from the turning of the meat on a spit (as a calque of Turkish döner into Greek). Doublet of gyre and gyrus.

Etymology from Wiktionary, CC BY-SA 3.0