Nouns

(n)subject, topic, themethe subject matter of a conversation or discussion“he didn't want to discuss that subject”, “it was a very sensitive topic”, “his letters were always on the theme of love”
(n)theme, motifa unifying idea that is a recurrent element in literary or artistic work“it was the usual ‘boy gets girl’ theme”
(n)theme, melodic theme, musical theme, idea(music) melodic subject of a musical composition“the theme is announced in the first measures”, “the accompanist picked up the idea and elaborated it”
(n)composition, paper, report, themean essay (especially one written as an assignment)“he got an A on his composition”
(n)root, root word, base, stem, theme, radical(linguistics) the form of a word after all affixes are removed“thematic vowels are part of the stem”

Verbs

(v)themeprovide with a particular theme or motive“the restaurant often themes its menus”