Rings from Circle Line stopping District Line ultimately (7)
I believe the answer is:
areolae
'rings' is the definition.
Although both the answer and definition are plural nouns, I can't understand how they can define each other.
'circle line stopping district line ultimately' is the wordplay.
'circle line' becomes 'ol' (I can't explain this - if you can you should believe this answer much more).
'stopping' is an insertion indicator (inserted letters stop or plug a gap).
'district' becomes 'area' (a district is a geographical area).
'ultimately' suggests the final letters.
The last letter of 'line' is 'e'.
'ol' going inside 'area' is 'areola'.
'areola'+'e'='AREOLAE'
'from' acts as a link.
Can you help me to learn more?