What does an air traffic controller mean by "line up and wait"?

The phrase "line up and wait" is a specific instruction given by air traffic controllers that means the aircraft is cleared to enter the runway and position itself for takeoff, but must hold there and wait for final clearance to actually take off. This instruction is important for managing runway use and ensuring safe separation between aircraft.

When an aircraft is told to "line up and wait," it indicates that there may be other traffic in the vicinity, and the controller needs to ensure that it is safe for the aircraft to take off before clearing it for departure. This procedure helps maintain order and safety at busy airports by allowing aircraft to line up in an orderly manner while managing the overall flow of air traffic on the runway.

The other choices do not accurately describe "line up and wait." For example, entering the runway and taking off immediately would represent a separate instruction, while taxiing to the gate signifies that the aircraft is finishing its operations rather than preparing to take off. Lastly, proceeding to the next waypoint is about in-flight navigation rather than runway operations.