The Collaborative International Dictionary
Cyclo-
Cyclo- \Cy"clo-\ (s?"kl?-). [Gr. ky`klos circle, wheel.] A combining form meaning circular, of a circle or wheel.
Douglas Harper's Etymology Dictionary
cyclo-
before a vowel, cycl-, word-forming element meaning "circle, ring, rotation," from Latinized form of Greek kyklo-, comb. form of kyklos "circle, wheel, ring" (see cycle (n.)).
Wiktionary
cyclo-
pre. 1 circle 2 cycle 3 (context chemistry English) a cyclic compound 4 (context meteorology English) cyclone