[uh b-zur-vuh-buh l]


capable of being or liable to be observed; noticeable; visible; discernible: an observable change in attitude.
worthy or important enough to be celebrated, followed, or observed: an observable holiday.
deserving of attention; noteworthy.

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. 2019

Examples from the Web for observable

Contemporary Examples of observable

  • The observable Universe contains around 100 billion large galaxies and a comparable number of supermassive black holes.

    The Daily Beast logo
    The Black Hole Tango

    Matthew R. Francis

    November 24, 2014

  • All ISIS logistics and dispositions in the field are observable by drone and satellite.

    The Daily Beast logo
    How a Real Air War Could Demolish ISIS

    Clive Irving

    August 23, 2014

  • Theory: a scientifically acceptable principle explaining a set of observable facts.

  • Global warming is an observable fact, and transportation emissions are the second largest contributor to the problem.

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    Pancakes' New Topper

    Stacey Slate

    December 8, 2009

  • How has this soldier demonstrated recurring actions, patterns, or observable behaviors that might indicate his real beliefs?

    The Daily Beast logo
    Why We Should Screen Muslim Soldiers

    Ken Allard

    November 27, 2009

Historical Examples of observable

  • Between the "wondering" and the noun there had been an observable pause.

  • On the 15th of September, 17—, an unusual stir was observable in our village.

  • The only other observable symptom was slightly increased thirst.

    Pariah Planet

    Murray Leinster

  • It is observable that he does not absolutely deny that there is an opposite of Being.



  • A tendency to a paradoxical manner of statement is also observable.



Word Origin and History for observable

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

Online Etymology Dictionary, © 2010 Douglas Harper

observable in Science



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