In cabin crew terminology, what does 'PU' refer to?

In cabin crew terminology, 'PU' refers to 'Purser'. The purser holds a vital role on an aircraft, serving as the lead flight attendant. This individual is responsible for managing the cabin crew, coordinating tasks, ensuring the safety and comfort of passengers, and acting as the primary point of communication between the flight deck and the cabin crew. The purser also handles administrative duties and oversees service quality, making their position essential for the smooth operation of the flight.

The other terms do not directly relate to the specific responsibilities and roles present in the aviation cabin crew context, making 'Purser' the most appropriate and relevant choice.