C - Chaos, Criteria, Crystal, Cyan, Cynic, Cycle, Cyclone, Cylinder, Center, Cord, Card, Clone, Cardiac.

Chaos. From Ancient Greek χάος, khaos, vast chasm, void. A condition or place of great disorder or confusion.

Derived or related words: chaotic, chaotically.

Criteria. The plural form of criterion, formed according to the Ancient Greek  κριτήριον, kriterion, a test, a means of judging. From κριτής, krites, a judge. From κρίνω, krinō, I judge.

Derived or related words: criterion.

Crystal. From Ancient Greek κρύσταλλος, krestallos, ice. From κρύος, kreos, frost. A piece of glimmering, shining mineral resembling ice or glass.

Derived or related words: crystalline, crystallite, crystallization, crystallize, crystalloid.

Cyan. From Ancient Greek κύανος, kyanos, dark blue, dark blue enamel. A greenish blue, one of the subtractive primary.

Derived or related words: cyanide, cyanogen, cyanosis, cyanotic.

Cynic. From Ancient Greek κυνικός, kynikós, originally derived from the portico in Athens called Κυνόσαργες, Kynosarges. Of or relating to the belief that human actions are motivated only or primarily by base desires or selfishness. Skeptical of the integrity, sincerity, or motives of others.

Derived or related words: cynical, cynicism, cynically.

Cycle. From Ancient Greek κύκλος, kyklos, circle. An interval of space or time in which one set of events or phenomena is completed. A complete rotation of anything.
(Also recycle. From re-, again and‎ cycle, see above. To break down and reuse component materials.)

Derived or related words: cyclic, cyclone, cyclist, bicycle, tricycle.

Cyclone. From Ancient Greek κυκλώνω, kyklono, to completely rotate. From κύκλος, kyklos, circle. A system of winds rotating around a center of low atmospheric pressure.

Derived or related words: cyclonic.

Cylinder. From Ancient Greek κύλινδρος, kylindros. From κυλίνδειν, to roll. A surface created by projecting a closed two-dimensional curve along an axis intersecting the plane of the curve.

Derived or related words: cylindrical, cylindrically.

Center. From Ancient Greek κέντρον, kéntron. From κεντεῖν, to prick, goad. The point in the interior of a circle or sphere that is equidistant from all points on the circumference.

Derived or related words: centered, centering, central, centrally. 

Cord. From Ancient Greek χορδά, khorda, Ionic χορδή, khorde, string of gut, the string of a lyre. Also, a small flexible electrical conductor composed of wires insulated separately or in bundles and assembled together usually with an outer cover.

Derived or related words: cordial, cordially.

Card. From Ancient Greek χάρτης, chartēs, paper, papyrus. Any flat, normally rectangular piece of stiff paper, plastic etc.

Derived or related words: cardboard, postcard etc.

Clone. From Ancient Greek κλών, klōn, twig. A living organism (originally a plant) produced asexually from a single ancestor, to which it is genetically identical.

Derived or related words: cloning.

Cardiac. From Ancient Greek καρδιακός, kardiakos. From καρδιά, kardia, heart. Relating to the heart.

Derived or related words: cardiology, myocardial, pericardium.