- [countable, usually singular]
one of the two imaginary lines drawn around the world 23° 26′ north (the Tropic of Cancer) or south (the Tropic of Capricorn) of the equator 回归线（北回归线称 the Tropic of Cancer，南回归线称 the Tropic of Capricorn） - the tropics[plural]
the area between the two tropics, which is the hottest part of the world 热带；热带地区
Word Originlate Middle English (denoting the point on the ecliptic reached by the sun at the solstice): via Latin from Greek tropikos, from tropē ‘turning’, from trepein ‘to turn’.