Pilot in command (PIC)

The pilot responsible for the operation and safety of the flight.

As taught in The Tests and What Your Certificate Lets You Do (Becoming a Private Pilot) — a free lesson with cited FAA sources.

The pilot with final authority and responsibility for the operation of the aircraft.

As taught in The Pilot in Command: Authority and Responsibility (Regulatory Framework and Pilot Responsibilities) — a free lesson with cited FAA sources.