Technical term for a device that measures or maintains orientation using angular momentum. The loanword ジャイロスコープ is also common.
See also: ジャイロスコープ
Gyroscopes are used for attitude control in aircraft.
Smartphones have a small gyroscope built in.
Compound of 回転 (rotation) and 儀 (instrument). The exact historical derivation is uncertain; the spelling is conventionally associated with the meaning 'gyroscope'.