Plain English Meaning

A spinning wheel inside the instrument that is tilted on purpose, so it can pick up two kinds of motion at once — the aircraft rolling onto its side and the aircraft turning.

Full Definition

A gyroscope mounted with its spin axis tilted (typically about 30 degrees up from horizontal) rather than vertical or horizontal. In a turn coordinator, this tilted mounting allows the instrument to sense both roll rate and yaw rate, so it indicates the rate at which the aircraft is rolling into or out of a turn as well as the rate of turn itself.

Context Anchor

Seen in instrument flying when learning how a turn coordinator works and why it reacts as the airplane begins to roll into a turn.