Involving the determination only of the presence or absence of a substance or condition, without regard to quantity. Thus a compass held near a wire might determine qualitatively whether a current was passing through the wire, but would not be sufficient to determine its quantity. (See Quantitative.)

Waves or periodic motions the angle of lag of one of which, with reference to one in advance of it, is 90°, are said to be in quadrature with each other. [Transcriber's note: If the voltage and current of a power line are in quadrature, the power factor is zero (cos(90°) = 0)  and no [...]

The accepted length of the quadrant of the earth, 9.978E8 instead of 1E9 centimeters; or to 9,978 kilometers instead of 10,000 kilometers.

A length equal to an approximate earth quadrant, equal to 1E9 centimeters. It has been used as the name for the unit of inductance, the henry, q. v. Synonym–Standard Quadrant.

(a) A contraction for quadrant, used as the unit of inductance; the henry. (b) A contraction for quadruplex in telegraphy. [Transcriber's note: A modern use of "quad" is a unit of energy equal to 1E15  (one quadrillion) BTU, or 1.055E18 joules. Global energy production in 2004 was 446 quad.]

Symbol for electric quantity.