A year's start (7)
I believe the answer is:
january
'start' is the definition.
The definition and answer can be both related to time as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'a year's' is the wordplay.
I cannot quite see how this works, but
'a' could be 'an' and 'an' is located in the answer.
'year' could be 'y' and 'y' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for january that I've seen is " First month".)