What does tropic mean?
A tropic is one of two imaginary lines of latitude situated about 23.5 degrees north and south of the equator. The northern line is the Tropic of Cancer, and the southern line is the Tropic of Capricorn; each marks the point where the Sun can appear directly overhead at the solstices. The plural “the tropics” denotes the broad equatorial zone between these lines, including regions such as the Caribbean, Central America, and parts of South America, Africa, Asia, and Oceania. As an adjective, tropic means associated with the tropics or with either of these geographical lines. The word is especially useful in geography, climatology, astronomy, and biology, where it distinguishes the equatorial region from the temperate and polar zones. Although often encountered in the formal names of the two tropic lines, it also occurs in compound expressions such as “tropic bird.” Its unusual history connects it to the turning of the Sun and, more broadly, to the ancient idea of turning or change.
Either of the two parallels of latitude approximately 23.5 degrees north or south of the equator, known respectively as the Tropic of Cancer and the Tropic of Capricorn. In the plural, the word refers to the equatorial regions between these parallels.
"The Tropic of Cancer marks the northern limit of the tropics."
The singular is most often used in the two formal line names; “the tropics” is the usual expression for the equatorial region as a whole.
Relating to the tropics or to either of the two parallels of latitude known as the tropics.
"The island supports tropic vegetation and a wide variety of tropical birds."
This use is more common in specialized geographical and biological writing than in everyday speech.
The plural is the standard way to refer collectively to the warm equatorial region between the Tropic of Cancer and the Tropic of Capricorn.
"Many species of monkeys are native to the tropics."
The word “tropic” comes from the idea of a turning point: the two tropic lines mark where the Sun reaches its northernmost and southernmost points in the year.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does tropic come from?
The word comes through Latin from Greek tropikos, “pertaining to a turning,” with tropē meaning “a turning” or “change.” The Greek term referred to the turning points of the Sun's apparent yearly movement, corresponding to the solstices. English borrowed the word in the late 16th century for the two solar or geographic turning lines, and related forms such as tropical and subtropical developed from the same root.
Related word forms
How tropic is actually used
The singular noun is chiefly used in the names “Tropic of Cancer” and “Tropic of Capricorn.” For the equatorial region as a whole, “the tropics” is much more common than “tropic.” The adjective is relatively technical and is often used in geographical or biological contexts.
Easily confused with tropic
A tropic is a geographic latitude or a region near the equator, whereas a topic is a subject or idea being discussed.