noun
participant; entrant; player; competitor
General term for someone who takes part in an event, meeting, competition, or activity. Covers attendees, contestants, and players.
会議の参加者は全員、事前に登録が必要です。
All participants in the meeting must register in advance.
トーナメントの
There are 32 entrants in the tournament.
出場者 is more specific to sports or stage appearances, emphasizing taking the field or stage, while 参加者 is broader.
Compound of 参加 (participation) + 者 (person). The reading is standard on'yomi.