tropo-

Turning; change.

Greek tropos, turning.

The troposphere is the lowest region of the atmosphere, which exhibits convection; it extends from the earth's surface to the tropopause, the interface between the troposphere and the stratosphere; tropomyosin is a protein involved in muscle contraction, myosin and occurs together with a related protein, troponin, in the thin filaments of muscle tissue. Tropology is the figurative use of language; a trope is a figurative or metaphorical use of a word or expression.