Crossword Genius

Tiny part of a cat (4)

Ross

I believe the answer is:

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

'tiny part' is the definition.
'atom' can be an answer for 'part' (I have seen 'Part of molecule ' mean 'atom' so perhaps 'part' could also mean 'atom'). I'm not certain of the 'tiny' bit.

'a cat' is the wordplay.
'cat' becomes 'tom' (a tom is a male cat).
'a'+'tom'='ATOM'

'of' is the link.

Can you help me to learn more?

(Other definitions for atom that I've seen before include "Basic unit of a chemical element", "Minute particle", "It was once thought to be smallest particle of matter", "type of bomb", "Very small object or amount".)