tropic
noun geography, environment uk/ˈtrɒp.ɪk/ us/ˈtrɑː.pɪk/
[ C ]回归线
one of the two imaginary lines around the earth at approximately 23.5 degrees north and 23.5 degrees south of the equator
the tropics[ plural ] 热带地区
the hottest area of the earth, between the Tropic of Cancer and the Tropic of Capricorn
She's a botanist and spent several years doing research in the tropics. 她是个植物学家，花了几年时间在热带地区做研究。