—n. 1. a subject of discourse, discussion, meditation, or composition; topic: The need for world peace was the theme of the meeting. 2. a unifying or dominant idea, motif, etc., as in a work of art.
3. a short, informal essay, esp. a school composition.
4. Music. a. a principal melodic subject in a musical composition.
b. a short melodic subject from which variations are developed.
5. Gram.the element common to all or most of the forms of an inflectional paradigm, often consisting of a root with certain formative elements or modifications. Cf. stem1 (def. 16).
6. Ling.topic (def. 4).
7. Also,thema.an administrative division of the Byzantine Empire.
—adj. having a unifying theme: a theme restaurant decorated like a spaceship.