One of the two small circles of the celestial sphere, situated on each side of the equator, at a distance of 23° 28&min;, and parallel to it, which the sun just reaches at its greatest declination north or south, and from which it turns again toward the equator, the northern circle being called the Tropic of Cancer, and the southern the Tropic of Capricorn, from the names of the two signs at which they touch the ecliptic.
- Either of two parallels of latitude on the earth, one 23°27ʹ north of the equator and the other 23°27ʹ south of the equator, representing the points farthest north and south at which the sun can shine directly overhead and constituting the boundaries of the Torrid Zone.
- The region of the earth's surface lying between these latitudes.
- Astronomy Either of two corresponding parallels of celestial latitude that are the limits of the apparent northern and southern passages of the sun.
- Of or relating to the Tropics; tropical.