A generation or part of it (3)
I believe the answer is:
era
This clue could be a double definition.
'a generation' is the first definition.
(I've seen this in another clue)
'part of it' is the second definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'or' acts as a link.
Can you help me to learn more?
(Other definitions for era that I've seen before include "Important time" , "Eon" , "Special time" , "Important date" , "Series of years" .)