This American's uncle (3)

I believe the answer is:

sam

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

'uncle' is the definition.
(Uncle Sam is an example)

'this american's' is the wordplay.
'SAM' is hidden in amongst the letters.
However, I'm unsure how this is indicated.

Can you help me to learn more?

(Other definitions for sam that I've seen before include "Boy" , "Casablanca piano player" , "together once" , "Uncle" .)

I've seen this clue in the Evening Standard.

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