An Oliver costume? (5)

I believe the answer is:

apron

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'an oliver costume?' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?

This is the entire clue.

Can you help me to learn more?

(Other definitions for apron that I've seen before include "Protective garment in kitchen" , "Projecting stage" , "area in front of aircraft hangar" , "Kitchen protector" , "conveyor-belt" .)

I've seen this clue in the Sydney Morning Herald.

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