Round, round small crisps (6)
I believe the answer is:
discos
'crisps' is the definition.
Although both the answer and definition are plural nouns, I can't see how one could define the other.
'round round small' is the wordplay.
'round' becomes 'disc' (disc is a kind of round).
'round' becomes 'o' (round can mean a round object).
'small' becomes 's' (abbreviation - e.g. clothes size).
'disc'+'o'+'s'='DISCOS'
Can you help me to learn more?
(Other definitions for discos that I've seen before include "Dances with recorded popular music" , "Halls for dancing to recorded music" , "Parties with music" , "Dance venues, in short" , "dance clubs" .)