Plain English Meaning

The line running from the nose to the tail of the airplane. When the airplane tips one wing down and the other wing up, it is rotating around this line.

Full Definition

The longitudinal axis of an airplane — an imaginary line running from the nose to the tail — about which the airplane rolls left or right. Movement around this axis is called bank or roll, and it is controlled primarily by the ailerons.

Context Anchor

Seen on the electronic attitude indicator when using the display to control pitch and bank.

Derivation

‘Bank’ comes from an old word for a sloping side or edge — the same as a riverbank. When an airplane banks, one wing slopes down and the other slopes up, just like the sloping sides of a hill. ‘Axis’ comes from the Latin for an or line — the line something around.