Billy, perhaps, though Charlie has one (3)
I believe the answer is:
can
'billy' is the definition.
(I've seen this before)
'charlie has one' is the wordplay.
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'has' means one lot of letters go next to another.
'one' becomes 'an' (I've seen this in other clues).
'c'+'an'='CAN'
'perhaps though' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for can that I've seen before include "prison" , "toilet" , "Is able; container" , "Cooler" , "has power" .)