Grounds or pastures say (4)

I believe the answer is:

lees

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'grounds' is the definition.
(I've seen this before)

I don't understand how the remainder of the clue works.

(Other definitions for lees that I've seen before include "Sediement or else" , "Deposit" , "Eels found in sediment" , "Sediment that settles at the bottom of wine" , "Dregs, sediment" .)

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

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