What are entries of the same year called
Solution 1:
You might be thinking of batch or cohort.
The batch of students that enrolled this year are very naughty.
The cohort of students that graduated last year have all found jobs.
Solution 2:
If you want to say the "the ____ of 2010", the word you're looking for is class:
a body of students or alumni whose year of graduation is the same
Merriam-Webster online, entry for class, n.