noise

Pronunciation: noyz

Definition:

1. Unwanted sound, particularly a complex sound that lacks a musical quality because its various frequencies that comprise it are not whole-or-partial number multiples (harmonics) of each other.
2. Unwanted additions to a signal not arising at its source; the 60-cycle frequency wave in an electrocardiogram; largely eliminated from machines after 1980 (includes visual noise on imaging studies).
3. Extraneous uncontrolled variables influencing the distibution of measurements in a set of data.

See: signal:noise ratio

[M.E., fr. O.Fr., fr. L.L. nausea, seasickness]

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