Rolling stones (7)
I believe the answer is:
marbles
This clue could be a double definition.
'rolling' is the first definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe there's a link between them I don't understand?
'stones' is the second definition.
(marble is a kind of stone)
Can you help me to learn more?
(Other definitions for marbles that I've seen before include "You'll be mad if you lose them" , "Sculptures" , "Game with alleys and taws" , "alleys, perhaps" , "Mind" .)