Quoted as being seen when heard (5)
I believe the answer is:
cited
'quoted' is the definition.
('cite' can be a synonym of 'quote')
'being seen when heard' is the wordplay.
I cannot really see how this works, but
'being' could be 'ted' (Ted is an example) and 'ted' is found in the answer.
This explanation may well be incorrect...
'as' is the link.
Can you help me to learn more?
(Other definitions for cited that I've seen before include "Called for" , "Summoned" , "Commended" , "Quoted or mentioned as example" , "Made reference to -- edict (anag)" .)