Time then changed a bit (5)
I believe the answer is:
tenth
'a bit' is the definition.
The definition and answer can be both quantities as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'time then changed' is the wordplay.
'time' becomes 't' (abbreviation).
'changed' indicates anagramming the letters.
'then' with letters rearranged gives 'enth'.
't'+'enth'='TENTH'
Can you help me to learn more?
(Other definitions for tenth that I've seen before include "Fraction; last in the hit parade?" , "Decimal part?" , "Fraction in tithe" , "Ordinal number" , "after nine" .)