Firm measures briefly making money (5)

I believe the answer is:

coins

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'money' is the definition.
(thesaurus)

'firm measures briefly' is the wordplay.
'firm' becomes 'co' (a firm is a company).
'measures briefly' becomes 'ins' (in is a kind of measure. I am not sure about the 'briefly' bit.).
'co'+'ins'='COINS'

'making' acts as a link.

Can you help me to learn more?

(Other definitions for coins that I've seen before include "change" , "Metal money" .)

I've seen this clue in The Globe and Mail.

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