She may embrace a pupil (4)

I believe the answer is:

iris

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'pupil' is the definition.
(thesaurus)

I don't understand the remainder of the clue.

(Other definitions for iris that I've seen before include "In the middle of which pupil is opening" , "Plant with sword-shaped leaves" , "Flag - surrounding pupil" , "Flag - part of eye" , "Film about writer _______ Murdoch" .)

I've seen this clue in the Evening Standard.

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