Incisions made by the houseman? (5)

I believe the answer is:

holes

I'm a little stuck... Click here to teach me more about this clue!

'incisions' is the definition.
The definition and answer can be both shapes as well as being plural nouns.
Maybe there's an association between them I don't understand?

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for holes that I've seen before include "Apertures" , "Scrapes" , "Openings" , "Cavities" , "Empty spaces" .)

I've seen this clue in the Evening Standard.

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