1, 2. Behind, after both refer to a position following something else. Behind applies primarily to position in space, and suggests that one person or thing is at the back of another; it may also refer to (a fixed) time: He stood behind the chair. You are behind the appointed time. After applies primarily to time; when it denotes position in space, it is not used with precision, and refers usually to bodies in motion: Rest after a hard day's work. They entered the room, one after another.