Source : Webster's Revised Unabridged Dictionary (1913)

Voltage \Vol"tage\, n. (Elec.)
   Electric potential or potential difference, expressed in
   volts.

Source : WordNet®

voltage
     n 1: the rate at which energy is drawn from a source that
          produces a flow of electricity in a circuit; expressed
          in volts [syn: {electromotive force}, {emf}]
     2: the difference in electrical charge between two points in a
        circuit expressed in volts [syn: {electric potential}, {potential},
         {potential difference}, {potential drop}]

Source : Free On-Line Dictionary of Computing

voltage
     
         (Or "potential difference", "electro-motive
        force" (EMF)) A quantity measured as a signed difference
        between two points in an electrical circuit which, when
        divided by the {resistance} in {Ohms} between those points,
        gives the current flowing between those points in {Amperes},
        according to {Ohm's Law}.  Voltage is expressed as a signed
        number of Volts (V).  The voltage gradient in Volts per metre
        is proportional to the force on a charge.
     
        Voltages are often given relative to "earth" or "ground" which
        is taken to be at zero Volts.  A circuit's earth may or may
        not be electrically connected to the actual earth.
     
        The voltage between two points is also given by the charge
        present between those points in {Coulombs} divided by the
        {capacitance} in {Farads}.  The capacitance in turn depends on
        the {dielectric constant} of the insulators present.
     
        Yet another law gives the voltage across a piece of circuit as
        its {inductance} in {Henries} multiplied by the rate of change
        of current flow through it in Amperes per second.
     
        A simple analogy likens voltage to the pressure of water in a
        pipe.  Current is likened to the amount of water (charge)
        flowing per unit time.
     
        (1995-12-04)