Hi Candidate,
Cut-off refers to the expected marks or the Least marks needed to get admission into any Institute based on previous years statistics. The cut-off greatly varies from college to college, and from Stream to Stream, and from Category too.
You have specific reservation criteria for different categories such as Scheduled castes, Schedule Tribes, Other Backward Classes, Girls Supremacy Qouta which makes the cut-off differ for different categories.
Hope that this answer helps you.