Measured in ohms

• Obstacle
• Z stands for it in electronics
• A material's opposition to the flow of electric current

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

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
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 ...

Wiktionary Word definitions in Wiktionary
n. 1 (label en physics) A measure of the opposition to the flow of an alternating current in a circuit; the aggregation of its resistance, and inductive and capacitive reactances; the ratio of voltage to current treated as complex quantities. 2 (label en ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1886, from impede + -ance .

Wikipedia Word definitions in Wikipedia
Impedance in Accelerator Physics is a quantity that characterizes the self interaction of a charged particle beam, mediated by the beam environment, such as the vacuum chamber , RF cavities, and other elements encountered along the accelerator or storage ...

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
noun COLLOCATIONS FROM CORPUS ■ ADJECTIVE high ▪ This provides a relatively high input impedance looking into their bases and a low output impedance at the emitters. ▪ Its high input impedance means that it does not load a signal source which it copies ...