If someone is on a shortlist, for example for a job or a prize, they are one of a small group of people who have been chosen from a larger group. The successful person is then chosen from the small group. If you've been asked for an interview you are probably on a short list of no more than six
If someone or something is shortlisted for a job or a prize, they are put on a shortlist. He was shortlisted for the Nobel Prize for literature several times