Organ visibly smaller than the heart (3)

I believe the answer is:

ear

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

'organ' is the definition.
(the ear is an organ)

'visibly smaller than the heart' is the wordplay.
'EAR' is hidden in amongst the letters.
However, I am unsure how the hidden word is indicated.

Can you help me to learn more?

(Other definitions for ear that I've seen before include "Listening organ" , "Fruiting head of a cereal" , "Shell-like; corn" , "Bit of corn" , "Seed-bearing part of wheat" .)

I've seen this clue in the Evening Standard.

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