observable

[ uhb-zur-vuh-buhl ]

adjective

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.

observable

/ əb-zûr′və-bəl /

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.
2. See also uncertainty principle

Other Words From

• ob·serva·bili·ty ob·serva·ble·ness noun
• ob·serva·bly adverb
• nonob·serva·ble adjective
• nonob·serva·bly adverb
• unob·serva·ble adjective

Word History and Origins

Origin of observable¹

1600–10; < Latin observābilis remarkable, equivalent to observā ( re ) to observe + -bilis -ble

Example Sentences

I felt I should try to live up to the occasion and present some new ideas, so I raised the question of how the axion field settles down after the Big Bang, and whether it might leave an observable relic.

From Quanta Magazine

He lived for 12 years after his diagnosis, and I would guess at least 17 years since his first observable symptoms.

From Ozy

In quantum mechanics, a particular property of a substance — electrical conductivity, say, or optical transparency or reflectivity — corresponds to the average or “expectation value” of an observable quantity.

From Quanta Magazine

According to some calculations, the cosmos might have cooled so quickly that the fabric of space-time became fractured, creating a network of whisper-thin tubes filled by pure energy that stretch across the breadth of the observable universe.

From Quanta Magazine

In terms of the quality of the pitches they make — as measured by observable factors such as velocity and movement — southpaws are simply not in the same league as righties.

From FiveThirtyEight

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

From The Daily Beast

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

From The Daily Beast

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

From The Daily Beast

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

From The Daily Beast

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

From The Daily Beast

And on these faces, there was a certain pettiness and coldness not observable on those of the poorer women.

From Project Gutenberg

Algernon spoke with his old bright smile; but two things were observable throughout this interview.

From Project Gutenberg

We must reason from laws of nature; from the uniformities which are observable in the fact of likeness or unlikeness.

From Project Gutenberg

A groove or depression is commonly observable in the stone, designed to receive the string.

From Project Gutenberg

A drift of thought—an elevation of style, is observable in their public speaking which is dropt in private conversation.

From Project Gutenberg

Related Words

• appreciable
• detectable
• discernible
• noticeable
• perceptible