A classic dream once in circulation (9)
I believe the answer is:
decameron
'a classic' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'dream once in circulation' is the wordplay.
'in circulation' is an anagram indicator.
'dream'+'once'='dreamonce'
'dreamonce' is an anagram of 'DECAMERON'.
Can you help me to learn more?
(Other definitions for decameron that I've seen before include "Boccaccio's best-known work" , "Collected tales" , "books" , "Collection of 100 short stories by Boccaccio - rename cod (anag)" , "One hundred stories" .)