场次 is a noun meaning 'number of showings' or 'screening session' — it counts individual performances of a film, play, or event (e.g., 三场次 'three showings'). It is not a synonym for the siblings listed: 成绩 is 'grades/achievement', 结尾 is 'ending', 上演 is the verb 'to stage', 插曲 is 'incidental music', and 悬念 is 'suspense' — none are confusable with 场次.