‘第几次’ is an interrogative phrase meaning 'how many times?' or 'which time (in a sequence)?' It combines three characters: 第 (dì, 'ordinal marker'), 几 (jǐ, 'how many / which number?'), and 次 (cì, 'time / occurrence'). Together, it asks for the ordinal position of an event in a repeated series — not just frequency (like 'how often?') but specifically 'the how-many-th time?'. It’s commonly used when referring to past or future repetitions of an action, especially in questions about experience or scheduled events.

This phrase functions as a noun phrase and always appears before a verb or at the beginning/middle of a question. It cannot stand alone; it requires context — usually followed by a verb (e.g., 来, 去, 吃, 考试) or embedded in a full sentence with 是 or 了. It implies counting distinct occurrences, not duration or intensity. Learners should avoid confusing it with ‘几次’ (jǐ cì), which means 'a few times' or 'how many times?' without ordinal nuance — ‘第几次’ always emphasizes order in sequence.