trop·ic¹ / ˈträpik/ • n. the parallel of latitude 23°26′ north (tropic of Cancer) or south (tropic of Capricorn) of the equator. ∎  Astron. each of two corresponding circles on the celestial sphere where the sun appears to turn after reaching its greatest declination, marking the northern and southern limits of the ecliptic. ∎  (the tropics) the region between the tropics of Cancer and Capricorn.• adj. another term for tropical (sense 1).trop·ic² • adj. 1. Biol. relating to, consisting of, or exhibiting tropism. 2. Physiol. variant spelling of trophic.

tropic †each of the two solstitial points XIV; each of the two circles of the celestial sphere touching the ecliptic at the solstitial points XVI; either boundary of the torrid zone; pl. region between these XIX; adj. tropical XVI. — late L. tropicus — Gr. tropikós
1. pert. to the ‘turning’ of the sun at the solstice,

2. fig., f. tropē turning; see prec., -IC.

So tropical pert. to a tropic XVI (of the torrid zone XVII); metaphorical XVI.

tropic the parallel of latitude 23°26′ north (tropic of Cancer) or south (tropic of Capricorn) of the equator; the tropics is the name given to the region between the tropics of Cancer and Capricorn. The word is recorded from late Middle English, denoting the point on the ecliptic reached by the sun at the solstice.

tropics See Cancer; Capricorn