时段 (shí duàn) refers to a defined block or slot of time, often with a specific purpose (e.g., prime time, rush hour, work shift). It differs from 期间 (qī jiān), which is a more general period during which something occurs, and from 间隔/间隙 (jiàn gé/jiàn xì), which emphasize the gap or break between events. For work shifts, 班 (bān) is the more common word.