1. An area of land: Usually territory refers to a large tract of land, like a region or a country.
2. The land and waters under the jurisdiction of a government: A territory is a large area whose borders are established by the terms of a government, and not by natural features like rivers or mountains.
3. A political subdivision of a country; a geographic region: Aterritory can be exemplified by a colonial possession, that is dependent on an external government, such as the territories of the Holy Roman Empire.
4. A subdivision of the United States that is not a state and is administered by an appointed or elected governor and elected legislature: Another territory is a similarly organized political subdivision of Canada and Australia.
5. An area for which a person is responsible as a representative or an agent: Tom was a a salesperson and had his own territory where he sold his articles. .
6. In biology, an area occupied by a single animal, mating pair, or group: It is usual for animals to vigorously defend their territory against intruders, especially those of the same species.
7. Etymology, about 1432, "land under the jurisdiction of a town, state, etc.", probably from Latin territorium "land around a town, domain, district", from terra "earth, land".

An alternate theory, somewhat supported by the vowels of the original Latin word, suggests derivation from terrere "to frighten"; as in terrible; therefore, territorium would mean "a place from which people are warned off".

The meaning of "any tract of land, district, region" is first indicated in 1610. Specific U.S. sense of "organized self-governing region not yet a state" is from 1799. Territorial waters is traced back to 1841; territorial imperative "animal need to claim and defend territory" is recorded from 1966.

A behavior pattern in animals consisting of the occupation and defense of a territory: Territoriality is the behavior pattern in some animals in which they tend to remain within a certain area, primarily for the purpose of feeding, mating, and rearing their young and importantly this area is defended against members of the same species and also sometimes with other similar species.