Ridge of coral etc. (4)
I believe the answer is:
reef
(Other definitions for reef that I've seen before include "Main bank" , "Rock in shallow water" , "marine hazard" , "Take in (part of sail)" , "portion of sail" .)
I believe the answer is:
reef
(Other definitions for reef that I've seen before include "Main bank" , "Rock in shallow water" , "marine hazard" , "Take in (part of sail)" , "portion of sail" .)