FINGER LAW 1 . In electricity and magnetism: It can refer to Fleming's law or Rule of the left hand: a conductor that is within a magnetic field perpendicular to it and by which a current is circulated, a force is created whose direction will depend on how both magnitudes (current and field) interact. In this way, the thumb determines the sense of force that driver will experience. 2 . Colloquially, refer to the designation of a person by mere preference, pointing the finger at him with his index finger. 3 . In Rome, in the fights in the colosseum, the emperor decided the life or death of the defeated gladiator by the position of his thumb : up , life; below , death .
