PIC stands for pilot in command, and it's the title given to the person who is responsible for the safety and operation of an aircraft during flight.

Center of gravity. Center of rotation. Balance point.

Point on the longitudinal axis of the airplane (can be in front of or behind airplane) from which distance measurements are taken.

Distance from datum

Moment (force that causes an object to rotate).

The weight of the aircraft including oil and unusable fuel.