Webster's Revised Unabridged Dictionary · 1913

Theme

Theme , noun

[Old English teme, Old French teme, French thème, Latin thema, Greek {not transcribed}, from {not transcribed} to set, place. See Do, and compare Thesis.]

1.
A subject or topic on which a person writes or speaks; a proposition for discussion or argument; a text.
My theme is alway one and ever was. — Chaucer
And when a soldier was the theme, my name Was not far off. — Shakespeare
2.
Discourse on a certain subject.
Then ran repentance and rehearsed his theme. — Piers Plowman
It was the subject of my theme. — Shakespeare
3.
A composition or essay required of a pupil. — Locke
4.
(Grammar) 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.
5.
That by means of which a thing is done; means; instrument. [Obsolete] — Swift
6.
(Music) The leading subject of a composition or a movement.