A chit, maybe, or a letter (5)
I believe the answer is:
aitch
'a letter' is the definition.
(aitch is the name for the letter H)
'a chit maybe' is the wordplay.
'maybe' indicates an anagram.
'chit' with letters rearranged gives 'itch'.
'a'+'itch'='AITCH'
'or' acts as a link.
(Other definitions for aitch that I've seen before include "that I will immediately succeed" , "The letter h in full" , "Letter sound that's often dropped?" , "Eighth letter of the English alphabet" , "It's dropped by Cockneys" .)