Madeline's little boy (3)

I believe the answer is:

del

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

'boy' is the definition.

'madeline's little' is the wordplay.
'DEL' is hidden within the letters.
But, I am uncertain how the hidden word is indicated.

Can you help me to learn more?

(Other definitions for del that I've seen before include "drew it" , "Mathematical symbol < , delegate" , "Derek (dim.)" , "- Boy (Only Fools and Horses)" .)

I've seen this clue in the Evening Standard.

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