Term time, I note (7,4)

I believe the answer is:

quarter tone

I'm a little stuck... Click here to teach me more about this clue!

'note' is the definition.
Both the definition and answer are singular nouns.
Perhaps they are linked in a way I don't understand?

'term time i' is the wordplay.
'term' becomes 'quarter' (quarter is a kind of term).
'time' becomes 't' (abbreviation).
'i' becomes 'one' (Roman numeral for one).
'quarter'+'t'+'one'='QUARTER-TONE'

Can you help me to learn more?

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.