subject

noun:a person or thing that is being discussed, described, or dealt with
- The subject of our conversation was the upcoming project.
noun:a branch of knowledge studied or taught in an educational institution
- Mathematics was her favorite subject in school.
noun:a citizen or member of a state who owes allegiance to its government or leader
- Every subject of the kingdom was expected to pay taxes.
noun:the noun or pronoun that performs the action of the verb in a sentence
- In the sentence 'The cat sat on the mat,' 'the cat' is the subject.
adjective:likely or prone to be affected by something, typically something undesirable
- He is subject to severe allergies in the spring.
adjective:dependent or conditional upon something
- The plan is subject to approval from the board.
adjective:under the authority, control, or influence of someone or something
- The region was subject to the emperor's rule.
verb:to cause or force to undergo a particular experience or treatment
- The researchers will subject the material to extreme temperatures.
verb:to bring under one's control or jurisdiction
- The emperor sought to subject all the neighboring lands.