Tropics, two parallels of latitude on either side of the equator, which mark the limits N. and S. of the sun's verticality to the earth's surface, the distance being in each case 23½°; the northern tropic is called the Tropic of Cancer, and the southern the Tropic of Capricorn.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Trophonius * Troppau