1550s, method of divination said to have been practiced by a person walking in a circle marked with characters or signs till he fell from dizziness, the inference being drawn from the place in the circle at which he fell; from Medieval Latin gyromantia, from Greek gyyros "circle" (see gyro- (n.)) + manteia "divination, oracle" (see -mancy).[gyromancy etymology, gyromancy origin, 英语词源]