theme
nounUK /θiːm/
US /θiːm/
The main idea or subject of a story, song, or event.
The theme of the book is friendship.
OTHER MEANINGS
2. A short tune that is played many times in a piece of music.
The hero's theme played whenever he appeared on screen.
3. A special design or style used to decorate a place or event.
The party had a pirate theme with hats and treasure maps.
4. A subject that someone talks or writes about a lot.
Safety was the main theme of his speech.