Fit a small part (3)

I believe the answer is:

apt

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

'fit' is the definition.
(thesaurus)

'a small part' is the wordplay.
'small part' becomes 'pt' (I've seen this in other clues. I am not sure about the 'small' bit.**).
'a'+'pt'='APT'

Can you help me to learn more?

(Other definitions for apt that I've seen before include "Pertinent" , "Inclined; appropriate" , "Apposite, appropriate" , "Fit, suitable" , "Appropriate for Pat" .)

I've seen this clue in The Times.

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