Meaning of “territory” - Learner’s Dictionary

territory

noun uk us /ˈterɪtəri/
LAND [ C, U ]

B2 land that is owned or controlled by a particular country:

Spanish territory
PERSON/ANIMAL [ C, U ]

B2 an area that an animal or person thinks belongs to them:

Cats like to protect their territory.
AREA OF KNOWLEDGE [ U ]

an area of knowledge or experience:

With this project we'll be moving into unknown territory.

(Definition of “territory” from the Cambridge Learner’s Dictionary © Cambridge University Press)