parallax

noun par·al·lax \ ˈper-ə-ˌlaks , ˈpa-rə- \

Definition of parallax

: the apparent displacement or the difference in apparent direction of an object as seen from two different points not on a straight line with the object; especially : the angular difference in direction of a celestial body as measured from two points on the earth's orbit

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Recent Examples of parallax from the Web

The researchers used an old method called trigonometric parallax, which calculates distance by tracking a single celestial object's apparent shift in position as seen from Earth's orbit in two separate places, months apart.

— marissa fessenden, Smithsonian, "Scientists Peek Across the Galaxy to the “Dark Side” of the Milky Way," 14 Oct. 2017
The team also has made record breaking measurements of parallax, a term that, boiled down, means a measurement of distance between objects in relation to each other.

— john wenz, Popular Mechanics, "A Never-Before-Seen Region of Our Galaxy, Revealed," 12 Oct. 2017
The phenomena, also known as parallax, allowed scientists to determine how elevated or sunken the features imaged by their Long-Range Reconnaissance Imager (LORRI) on New Horizons were.

— doris elin salazar space.com staff writer, Fox News, "NASA unveils new maps of Pluto, Moon Charon for flyby anniversary," 17 July 2017
Measuring these shifts, or parallaxes, lets astronomers calculate the stars’ actual positions and movements through the galaxy with great precision, a field of study called astrometry that Gaia and its predecessor Hipparcos have revitalized.

— michael greshko, National Geographic, "New Milky Way Map Is a Spectacular Billion-Star Atlas," 14 Sep. 2016
By carefully directing light, Sharp's display uses a filter called a parallax barrier to transform that blur into 3-D magic – no lame eyewear required.

— wired staff, WIRED, "WIRED TOOLS 2K3," 1 Dec. 2003

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'parallax.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of parallax

Middle French parallaxe, from Greek parallaxis, from parallassein to change, from para- + allassein to change, from allos other

NEW! Time Traveler

First Known Use: 1580

in the meaning defined above

See Words from the same year

Other Astronomy Terms

gibbous, nadir, nebulous, penumbra, retrograde, sidereal, syzygy, wane, wax, zenith

Medical Dictionary

parallax

noun par·al·lax \ ˈpar-ə-ˌlaks \

medical Definition of parallax

: the apparent displacement or the difference in apparent direction of an object as seen from two different points not on a straight line with the object