Describing the main area on ice, possibly - cold (7)
I believe the answer is:
oceanic
'describing the main' is the definition.
The definition suggests a singular noun which matches the answer.
'area on ice possibly cold' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'possibly' indicates an anagram.
'cold' becomes 'C' (eg on taps).
'a'+'on'+'ice'='aonice'
'aonice' with letters rearranged gives 'oceani'.
'oceani'+'c'='OCEANIC'
Can you help me to learn more?
(Other definitions for oceanic that I've seen before include "description of rollers" , "Relating to the open seas" , "Pelagic" , "Huge" , "Like the main" .)