All 3 Uses of

theme

in

After the First Death

Someone had written a theme paper on the topic: in school.
Part 6 *

theme = an essay written by a student

Your papers are piled in a neat stack near the typewriter; a theme paper, I suppose.
Part 7

Definitions:

(1) (theme as in: theme of the novel)
a basic idea that underlies what is being said or done -- especially in a literary or artistic work
(2) (theme as in: musical theme)
the initial or primary melody of a musical composition

or

(as in "theme song") music that is most repeated in a film, television series, or other theatrical production
(3) (theme as in: wrote a 2-page theme on my summer)
an essay written by a student

(This sense of theme is much rarer in recent decades than in the past.)
(4) (meaning too rare to warrant focus)