Subject

Subject is a term with multiple meanings across disciplines. In grammar, the subject is the syntactic unit, usually a noun phrase, that performs the action of the verb or is described by it. In philosophy and cognitive science, the subject refers to a conscious being or the bearer of experiences, often contrasted with the object. In research and medicine, a subject is a person or animal who is studied or treated. In art, literature, and music, the subject is the topic, theme, or depicted entity. In education, a subject denotes a field of study such as mathematics or history.

Etymology: from Latin subjectus, past participle of subicere “to throw under” or “to subject to,” related to bringing under authority or consideration. The sense of a person or thing being presented for examination emerged in later usage.

Grammar specifics: the subject typically agrees in number with the verb. English word order is Subject-Verb-Object, although the subject may appear after an adverb or in questions. A subject can be a simple noun, a noun phrase, or a pronoun. In logic and philosophy, the subject term denotes the object of predication.

Usage notes: common phrases include subject matter, subject to conditions, and subject line. The term should be distinguished from object, which is the entity that receives an action or is described; in research ethics, a “subject” refers to a participant with rights that must be respected.