theme

(music) melodic subject of a musical composition.

“the theme is announced in the first measures”

An essay (especially one written as an assignment).

(linguistics) the form of a word after all affixes are removed.

The subject matter of a conversation or discussion.

“his letters were always on the theme of love”

A unifying idea that is a recurrent element in literary or artistic work.

“it was the usual `boy gets girl' theme”

Provide with a particular theme or motive.

“the restaurant often themes its menus”