early 14c., "person under control or dominion of another," from Old French suget, subget "a subject person or thing" (12c.), from Latin subiectus, noun use of past participle of subicere "to place under," from sub "under" (see sub-) + combining form of iacere "to throw" (see jet (v.)). In 14c., sugges, sogetis, subgit, sugette; form re-Latinized in English 16c.
Meaning "person or thing that may be acted upon" is recorded from 1590s. Meaning "subject matter of an art or science" is attested from 1540s, probably short for subject matter (late 14c.), which is from Medieval Latin subjecta materia, a loan translation of Greek hypokeimene hyle (Aristotle), literally "that which lies beneath." Likewise some specific uses in logic and philosophy are borrowed directly from Latin subjectum "foundation or subject of a proposition," a loan-translation of Aristotle's to hypokeimenon. Grammatical sense is recorded from 1630s. The adjective is attested from early 14c.