They charge around lake, stopping to change (7)
I believe the answer is:
cavalry
'they charge' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'around lake stopping to change' is the wordplay.
'around' becomes 'ca' (circa).
'lake' becomes 'L' (geographical abbreviation).
'stopping' indicates putting letters inside (stopping can mean blocking a gap).
'to change' becomes 'vary' ('vary' can be a synonym of 'change').
'l' placed into 'vary' is 'valry'.
'ca'+'valry'='CAVALRY'
Can you help me to learn more?
(Other definitions for cavalry that I've seen before include "Horse-soldiers" , "Military unit" , "Mounted troops" , "Horse soldiers" , "Mounted soldiers" .)