What is Tropics?

Legal Definition
The tropics are a region of the Earth surrounding the equator. They are delimited in latitude by the Tropic of Cancer in the Northern Hemisphere at 23°26′13.5″ (or 23.43707°) N and the Tropic of Capricorn in the Southern Hemisphere at 23°26′13.5″ (or 23.43707°) S; these latitudes correspond to the axial tilt of the Earth. The tropics are also referred to as the tropical zone and the torrid zone (see geographical zone). The tropics include all the areas on the Earth where the Sun is at a point directly overhead at least once during the solar year (which is a subsolar point).

The tropics are distinguished from the other climatic and biomatic regions of Earth, which are the middle latitudes and the polar regions on either side of the equatorial zone.
-- Wikipedia
Legal Definition
Region lying between the Tropic of Cancer, north of the Equator and the Tropic of Capricorn, south of the Equator.