A great area for sailing (5)
I believe the answer is:
ocean
'sailing' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'a great area' is the wordplay.
I cannot really see how this works, but
'a' could be 'an' and 'an' is found in the answer.
This explanation may well be incorrect...
'for' is the link.
Can you help me to learn more?
(Other definitions for ocean that I've seen before include "Major sea" , "lot of liquid" , "Large amount of water and" , "Quantity of water" , "Large stretch of water" .)