[1] : The Collaborative International Dictionary of English v.0.48

impedance \imped"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 = 2pifl, where f = frequency and l =
   self-inductance; for a circuit with capacity x = 1 div
   2pifc, where c = capacity.
   webster 1913 suppl.
see also:
2 

[2] : WordNet (r) 2.0

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

[3] : Moby Thesaurus II by Grady Ward, 1.0

18 moby thesaurus words for "impedance":
   capacitive reactance, clog, cumbrance, electric resistance,
   hindrance, impediment, inductive reactance, magnetic reluctance,
   ohm, ohmage, reactance, reluctance, reluctivity, resistance,
   skin effect, specific reluctance, surface resistance,
   volume resistance

Impedance >> I Words
Impedance, definition of term: Impedance
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