1. Force; power.
2. Physical force. Moral power.
(Science: physiology) principle of vis viva, living force; the force of a body moving against resistance, or doing work, in distinction from vis mortua, or dead force; the kinetic energy of a moving body; the capacity of a moving body to do work by reason of its being in motion. See kinetic energy, in the note under Energy. The term vis viva is not usually understood to include that part of the kinetic energy of the body which is due to the vibrations of its molecules.