parallax

[ par-uh-laks ]

/ ˈpær əˌlæks /

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noun

the apparent displacement of an observed object due to a change in the position of the observer.

Astronomy. the apparent angular displacement of a celestial body due to its being observed from the surface instead of from the center of the earth (diurnal parallax, or geocentric parallax ) or due to its being observed from the earth instead of from the sun (annual parallax or heliocentric parallax ).Compare parallactic ellipse.

the difference between the view of an object as seen through the picture-taking lens of a camera and the view as seen through a separate viewfinder.

an apparent change in the position of cross hairs as viewed through a telescope, when the focusing is imperfect.

Digital Technology. a 3D effect observed when images and other elements in the foreground of a screen move at a different rate than those in the background (often used attributively): parallax scrolling;Does this phone have parallax?

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Origin of parallax

First recorded in 1585–95; from Greek parállaxis “alternation, change of position” derivative of parallássein “to cause to alternate,” equivalent to para- + allássein “to change, alter, vary” (derivative of állos “other”) + -sis;see origin at para-¹, allo--sis

OTHER WORDS FROM parallax

par·al·lac·tic

[par-uh-lak-tik], /ˌpær əˈlæk tɪk/, adjectivepar·al·lac·ti·cal·ly, adverb

Words nearby parallax

paralipomena, Paralipomenon, paralipsis, parallactic ellipse, parallactic motion, parallax, parallel, parallel bars, parallel circuit, parallel cousin, parallel cousin marriage

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use parallax in a sentence

Worse, this parallax “offset” depends in complicated ways on objects’ positions, colors and brightness.
Astronomers Get Their Wish, and a Cosmic Crisis Gets Worse|Natalie Wolchover|December 17, 2020|Quanta Magazine
The astronomer Tycho Brahe didn’t detect any such stellar parallax and thereby concluded that Earth does not move.
Astronomers Get Their Wish, and a Cosmic Crisis Gets Worse|Natalie Wolchover|December 17, 2020|Quanta Magazine
Although a series of papers by Madore and Freedman’s team aren’t expected for a few weeks, they noted that the new parallax data and correction formula appear to work well.
Astronomers Get Their Wish, and a Cosmic Crisis Gets Worse|Natalie Wolchover|December 17, 2020|Quanta Magazine
One of the biggest sources of that uncertainty has been the distances to nearby stars — distances that the new parallax data appears to all but nail down.
Astronomers Get Their Wish, and a Cosmic Crisis Gets Worse|Natalie Wolchover|December 17, 2020|Quanta Magazine

They couldn't measure the parallax to the nearest star, so they would have no idea of stellar distances.
Islands of Space|John W Campbell
The most obvious and direct method is to determine the parallactic motion of the stars of known parallax.
The Popular Science Monthly, September, 1900|Various
The parallax decreases as the distance of the body increases.
Essays|Ralph Waldo Emerson
Life becomes awful by its reaches: its span from zenith to nadir, by moral parallax.
The Atlantic Monthly, Vol. 13, No. 76, February, 1864|Various
The efforts to discover stellar parallax were, of course, still continued.
The Popular Science Monthly, October, 1900|Various

British Dictionary definitions for parallax

parallax

/ (ˈpærəˌlæks) /

noun

an apparent change in the position of an object resulting from a change in position of the observer

astronomy the angle subtended at a celestial body, esp a star, by the radius of the earth's orbit. Annual or heliocentric parallax is the apparent displacement of a nearby star resulting from its observation from the earth. Diurnal or geocentric parallax results from the observation of a planet, the sun, or the moon from the surface of the earth

Derived forms of parallax

parallactic (ˌpærəˈlæktɪk), adjectiveparallactically, adverb

Word Origin for parallax

C17: via French from New Latin parallaxis, from Greek: change, from parallassein to change, from para- 1 + allassein to alter

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for parallax

parallax

[ păr′ə-lăks′ ]

A change in the apparent position of an object relative to more distant objects, caused by a change in the observer's line of sight towards the object. The parallax of nearby stars caused by observing them from opposite points in Earth's orbit around the Sun is used in estimating the stars' distance from Earth through triangulation.