• synonyms


[uh b-zur-vuh-buh l]
  1. capable of being or liable to be observed; noticeable; visible; discernible: an observable change in attitude.
  2. worthy or important enough to be celebrated, followed, or observed: an observable holiday.
  3. deserving of attention; noteworthy.
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Origin of observable

1600–10; < Latin observābilis remarkable, equivalent to observā(re) to observe + -bilis -ble
Related formsob·serv·a·bil·i·ty, ob·serv·a·ble·ness, nounob·serv·a·bly, adverbnon·ob·serv·a·ble, adjectivenon·ob·serv·a·bly, adverbun·ob·serv·a·ble, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for observably

Historical Examples of observably

  • And therefore also it is prodigious to have thunder in a clear sky, as is observably recorded in some Histories.

    The Works of Sir Thomas Browne (Volume 1 of 3)

    Thomas Browne

  • There were eleven of them; all were deeply excited, and two or three of the younger men were observably drunk and reckless.

Word Origin and History for observably



c.1600, from Latin observabilis "remarkable, observable," from observare (see observe). Related: Observably; observability.

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Online Etymology Dictionary, © 2010 Douglas Harper

observably in Science


  1. 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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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.