What goes up when it really comes down? (8)

I believe the answer is:

umbrella

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'down?' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe you can see a link between them that I can't see?

I don't understand the rest of the clue.

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(Other definitions for umbrella that I've seen before include "Collapsible ribbed canopy against rain" , "Handheld collapsible canopy" , "Rain protector" , "Protection that can be rolled up" , "Comprehensive" .)

I've seen this clue in The Sun.

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