"of or characteristic of the legendary Cyclopes of Greek mythology," 1640s, from Latin cyclopeus, from Greek kyklopeios, from kyklopes (see cyclops). Especially in reference to having a single eye in the middle of the forehead; also "vast, gigantic," and in reference to a style of ancient masonry, irregular or unhewn, fabled to be the work of a gigantic Thracian race (1822).