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Origin of observable
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
c.1600, from Latin observabilis "remarkable, observable," from observare (see observe). Related: Observably; observability.
Online Etymology Dictionary, © 2010 Douglas Harper
A measurable property of a physical system, such as mass or momentum. In quantum mechanics, observables correspond to mathematical operators used in the calculation of measurable quantities. Operators that do not commute, having a nonzero commutator, correspond to observables that cannot be precisely measured at the same time, such as momentum and position. See also uncertainty principle.
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