Muses say hr/3600 is briefer than brief (7)
I believe the answer is:
sisters
'muses' is the definition.
The answer and definition can be both people as well as being plural nouns.
Maybe you can see a link between them that I don't see?
'hr3600 is briefer than brief' is the wordplay.
I cannot really see how this works, but
'is' is within the answer.
This explanation may well be incorrect...
'say' acts as a link.
Can you help me to learn more?
(Other definitions for sisters that I've seen before include "Nuns - nurses - siblings" , "Resists for relatives" , "Female siblings" , "Resists (anag)" , "Relatives in hospital?" .)