时候 (shí hou) refers to a specific point in time or moment when something happens, like in '什么时候' (what time) or '这个时候' (at this time). It differs from 时间 (shí jiān), which is about duration or the abstract concept of time (e.g., 'no time'). Use 时候 to mark an event's 'when' and 时间 for 'how long'.