Prudence has delayed opening sale (7)

I believe the answer is:

auction

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

I cannot understand how the rest of the clue works.

(Other definitions for auction that I've seen before include "A lot will be seen in this" , "Where things are sold to the highest bidder" , "Public sale by bid" , "Public sale with lots" , "Public sale at which bids are made" .)

I've seen this clue in The Independent.

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