Coral, for one (3)
I believe the answer is:
sea
'coral for one' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sea that I've seen before include "All at . . . - totally confused" , "Ocean area" , "Vast expanse" , "E.g. Baltic" , "Eg, Aral, Ross, Irish" .)