impedance (countable and uncountable, plural impedances)
The act of impeding; that which impedes; a hindrance.
(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.
(physics) A quantity analogous to electrical impedance in some other energy domain
(physics, usually with “mechanical”) a measure of opposition to motion of something subjected to a force; the ratio of force to velocity treated as complex quantities.
(physics, usually with “acoustic” or “sound”) the ratio of sound pressure to volume flow rate treated as complex quantities.
(by analogy, software engineering, usually with “mismatch”) a measure of the opposition caused by differences between two paradigms, especially between object-oriented development and relational databases
Impedance is universally given the symbol Z in technical works which is often used as a synonym for the word even in running text.
Source: Wiktionary
Im*ped"ance, n. [Impede + -ance.] (Elec.)
Definition: 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 R2 + X2, where R = ohmic resistance, X = reactance. For an inductive circuit, X = 2pfL, where f = frequency and L = self-inductance; for a circuit with capacity X = 1 Ă· 2pfC, where C = capacity.
Source: Webster’s Unabridged Dictionary 1913 Edition
21 February 2025
(noun) some artifact that has been restored or reconstructed; “the restoration looked exactly like the original”
The first coffee-house in Mecca dates back to the 1510s. The beverage was in Turkey by the 1530s. It appeared in Europe circa 1515-1519 and was introduced to England by 1650. By 1675 the country had more than 3,000 coffee houses, and coffee had replaced beer as a breakfast drink.
