Possibly learns about a reserve of strength (7)
I believe the answer is:
arsenal
'reserve of strength' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'possibly learns about a' is the wordplay.
'possibly' indicates anagramming the letters.
'about' indicates putting letters inside.
'learns' anagrammed gives 'arsenl'.
'arsenl' going around 'a' is 'ARSENAL'.
Can you help me to learn more?
(Other definitions for arsenal that I've seen before include "Where the guns are and who are The Gunners are" , "stock" , "munitions factory" , "2014 and 2015 FA Cup winners" , "London FC" .)