(1):
(n.) The leading subject of a composition or a movement.
(2):
(n.) A noun or verb, not modified by inflections; also, that part of a noun or verb which remains unchanged (except by euphonic variations) in declension or conjugation; stem.
(3):
(n.) Discourse on a certain subject.
(4):
(n.) A composition or essay required of a pupil.
(5):
(n.) A subject or topic on which a person writes or speaks; a proposition for discussion or argument; a text.
(6):
(n.) That by means of which a thing is done; means; instrument.