Tropic  —n. 1 parallel of latitude 23°27´ north (tropic of cancer) or south (tropic of capricorn) of the equator. 2 each of two corresponding circles on the celestial sphere where the sun appears to turn when at its greatest declination. 3 (the tropics) region between the tropics of cancer and capricorn. —adj. = *tropical. [greek trope turn]