It's another way to say "waitlisted." Schools will try to fill their classes with accepted students and if they haven't by the time they complete an interview cycle they begin to pull students from the list. Some schools only have one "cycle" per year, others will dip into the list more than once a year, like LECOM-B does in Dec. Many schools will rank their waitlist, giving you a number, 1 being the best, or high/mid/low, high being the best. You can still update with things you do such as grades, additional LORs or volunteer work. They may not get you off the list on their own but can certainly help.