Sailor gets half a shield (5)

I believe the answer is:

targe

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'a shield' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's a link between them I don't understand?

'sailor gets half' is the wordplay.
'sailor' becomes 'tar' (slang term for a sailor).
'half' indicates taking half.
'gets' halved is 'ge'.
'tar'+'ge'='TARGE'

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.

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