impedance
    n 1: a material's opposition to the flow of electric current;
         measured in ohms [syn: electric resistance, electrical
         resistance, impedance, resistance, resistivity,
         ohmic resistance]

Impedance \Im*ped"ance\, n. [Impede + -ance.] (Elec.)
   The apparent resistance in an electric circuit to the flow of
   an alternating current, analogous to the actual electrical
   resistance to a direct current, being the ratio of
   electromotive force to the current. It is equal to root{R^2
   + X^2, where R = ohmic resistance, X = reactance. For an
   inductive circuit, X = 2[pi]fL, where f = frequency and L =
   self-inductance; for a circuit with capacity X = 1 [div]
   2[pi]fC, where C = capacity.
   [Webster 1913 Suppl.]

impedance

    Opposition to flow of alternating
   current.  Impedance consists of resistance plus reactance
   (capacitive or inductive).  Measured in Ohms.

   (2003-12-02)