Keyhole operation (5)

I believe the answer is:

event

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'keyhole operation' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?

This is the entire clue.

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(Other definitions for event that I've seen before include "A noteworthy happening or occurrence" , "Something that happens - part of a programme?" , "Something taking place" , "Something happening" , "Planned public or social occasion" .)

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

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