noun
group stage; pool stage
Wasei-eigo term used in sports tournaments to refer to the preliminary round-robin phase before knockout rounds.
wasei-eigo (Japanese-coined English), from group league
ワールドカップのグループリーグで日本が勝ち進んだ。
Japan advanced through the group stage of the World Cup.
グループリーグの結
The group stage results determined which teams would advance to the knockout round.