One on hand to vote late? (6)

I believe the answer is:

pollex

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'one on hand' is the definition.
The definition and answer can be both body parts as well as being singular nouns.
Maybe they are linked in a way I don't understand?

'vote late?' is the wordplay.
'vote' becomes 'poll' (polling is a kind of voting).
'late?' becomes 'ex'.
'poll'+'ex'='POLLEX'

'to' acts as a link.

Can you help me to learn more?

I've seen this clue in The Guardian.

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