The phrase "short notice" refers to a situation where something is required or needed at very short time, often with little or no advance warning. It means that there isn't enough time for proper planning and preparation before an event takes place. The term can be used in various contexts such as giving someone a task to do, making arrangements for an appointment or meeting, or asking someone to come quickly to a particular place. In essence, it implies that the person being addressed needs to act promptly without delay because there isn't enough time to waste.