Recurring musical phrase (9)

I think it could be either:

Which length description are you looking for?:

motto

'recurring musical phrase' is the definition.
(I've seen this before)

This is the entire clue.

(Other definitions for motto that I've seen before include "Phrase in a Christmas cracker" , "Short sentence adopted as rule of conduct" , "Watchword" , "Guiding adage" , "cry" .)

I've seen this clue in The Times.

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