All 4 Uses

theme
in
Wonder, by R.J. Palacio
(Edited)

Didn't you notice they changed the theme of the New Year Art Show? In past years fifth graders painted self-portraits, but this year they made us do those ridiculous self-portraits as animals, remember?
p. 171.8

theme = basic idea
While reading up on his life in preparation for this award, I came upon a passage that he wrote that seemed particularly consistent with the themes I touched on earlier, ... Not just the nature of kindness, but the nature of one's kindness. The power of one's friendship. The test of one's character. The strength of one's courage—
p. 303.7 *

themes = basic ideas
...themes I've been ruminating upon all year long.
p. 303.7
I could almost hear the Star Wars theme music playing in my head as I stood on the stage.
p. 306.6 *

theme = music that is most repeated in a film

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)