A play-in game is a game, usually played at the beginning of a tournament or just prior to the tournament depending on how the tournament is defined. In a play-in, the lowest qualifiers and/or participants who have earned conditional qualification compete for qualification to the main portion of the tournament.
A pre-tournament game is a game that occurs at the beginning of a tournament or just before it starts, depending on how the tournament is organized. In this preliminary round, the lowest-ranked players and/or those who have earned conditional qualification compete to earn a spot in the main tournament.