Coral component (5)
I believe the answer is:
polyp
'coral component' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for polyp that I've seen before include "Minute reef-building creature" , "Small tumour" , "Small unwanted growth in the body" , "Small growth on a mucous membrane" , "Coral form" .)