'待定' literally combines '待' (to wait, to be pending) and '定' (to decide, to fix), meaning 'pending decision' or 'to be determined'. It functions as an adjective describing something whose status, time, location, or details have not yet been finalized. It is commonly used in formal or semi-formal contexts—such as schedules, meeting agendas, project plans, or official announcements—to indicate provisional or undecided information.

The term conveys neutrality and professionalism; it avoids commitment while acknowledging that a resolution will follow. Unlike more casual alternatives like '还没定', '待定' sounds objective and administrative. It often appears after nouns (e.g., 时间待定, 地点待定) or as a standalone phrase in bullet-point lists or tables. While grammatically adjectival, it rarely takes aspect markers or degree modifiers—it’s typically used predicatively or attributively without modification.