Definition
A gyroscope whose rotor is spun by an electric motor powered from the aircraft's electrical system, rather than by a stream of air from a vacuum or pressure pump. The spinning rotor maintains a fixed orientation in space, allowing the instrument it drives to sense changes in aircraft attitude or rate of turn.
Plain English
A spinning wheel inside a flight instrument that is kept spinning by an electric motor. Because the wheel resists changes in its spinning direction, the instrument can use it to detect how the aircraft is moving.
Context Anchor
Seen in discussions of the turn coordinator and other cockpit instruments that use gyros for attitude or turn information.
Derivation
Gyroscope comes from the Greek 'gyros' (circle or turn) and 'skopein' (to look at or observe) -- literally a device for observing turning. 'Electrically-powered' simply specifies that the spin comes from electricity, not from suction or pressurized air.
Why Pilots Care
Supplies reliable gyroscopic information without depending on engine vacuum, giving redundancy if the vacuum system fails.
Analogy
It is like a toy top kept spinning by a small motor. As long as it keeps spinning, it resists being tipped suddenly, and that steady behavior can be used to sense movement.
Intuition Check
Electrically-powered does not mean the gyroscope measures electricity. It means electricity is what keeps the gyro spinning.
Example Sentence 1
The turn coordinator in this aircraft uses an electrically-powered gyroscope, so it will keep working even if the vacuum pump fails.
Example Sentence 2
Many modern trainers rely on an electrically-powered gyroscope for the turn coordinator because it needs no vacuum lines.