Crossword Genius

Iris may have one, so have you and I (9)

Ross

I believe the answer is:

diaphragm

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'iris' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I don't see?

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for diaphragm that I've seen before include "Partitioning membrane" , "Partition between thorax and abdomen" , "It separates the thorax from the abdomen" , "Flexible membrane" , "Thin dividing membrane" .)

I've seen this clue in the Evening Standard.
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