Last Chance Qualifier
A Last Chance Qualfier (LCQ for short) is a tournament held the day and/or night before a invitation-only event such as a Pro Tour or Nationals. The winner of a LCQ qualifies for the next day's tournament.
There are often several LCQs for an event. Players who enter a LCQ and then drop out as soon as they appear out of contention in order to enter another LCQ are said to be "grinding in". LCQs often last into the AM hours so players who manage to win one usually face a difficult and sleep-deprived tournament the next day.