parallax
noun
par·al·lax ˈper-ə-ˌlaks 
ˈpa-rə-
: 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
Example Sentences
Recent Examples on the Web The first rung—that is, the one concerning the nearest cosmic objects—relies on geometric parallax to determine the distance to special stars called Cepheid variables, which pulsate in proportion to their intrinsic luminosity. 
Anil Ananthaswamy, Scientific American, 18 Apr. 2022 This included multiple Commander Keen side-scrolling games, and id Software began the year of 1992 by prototyping the game that would have been Keen 7, whose major technological advancement would have been parallax-scrolling backgrounds. Sam Machkovech, Ars Technica, 24 Mar. 2022 Rowan-Robinson says that shifts in position for planetary candidates would have been due to parallax, as the Earth orbited the sun causing the position of the IRAS to change angles. Joshua Hawkins, BGR, 16 Nov. 2021 The engine’s constraints forced tricks and fixes, like using parallax effects to mimic perspectives that are otherwise impossible in a 2D world, or generating entirely new spaces just to fake a mirror effect. Will Pritchard, Wired, 13 Nov. 2021 Accurate distance measurements with cameras requires spreading cameras apart to achieve parallax. Sam Abuelsamid, Forbes, 2 Sep. 2021 The high alleged speeds and turn rates of the objects reported by some witnesses are not shown in the video, but could easily be explained by parallax. Andrew Follett, National Review, 21 May 2021 The parallax effect also offers a more mundane explanation of the Go Fast video, West contends. Andrew Dyer, San Diego Union-Tribune, 29 May 2021 And yet, no matter how acute your vision was, nobody had ever observed a parallax for any of the stars in the sky. Ethan Siegel, Forbes, 10 Mar. 2021 See More
Anil Ananthaswamy, Scientific American, 18 Apr. 2022 This included multiple Commander Keen side-scrolling games, and id Software began the year of 1992 by prototyping the game that would have been Keen 7, whose major technological advancement would have been parallax-scrolling backgrounds. Sam Machkovech, Ars Technica, 24 Mar. 2022 Rowan-Robinson says that shifts in position for planetary candidates would have been due to parallax, as the Earth orbited the sun causing the position of the IRAS to change angles. Joshua Hawkins, BGR, 16 Nov. 2021 The engine’s constraints forced tricks and fixes, like using parallax effects to mimic perspectives that are otherwise impossible in a 2D world, or generating entirely new spaces just to fake a mirror effect. Will Pritchard, Wired, 13 Nov. 2021 Accurate distance measurements with cameras requires spreading cameras apart to achieve parallax. Sam Abuelsamid, Forbes, 2 Sep. 2021 The high alleged speeds and turn rates of the objects reported by some witnesses are not shown in the video, but could easily be explained by parallax. Andrew Follett, National Review, 21 May 2021 The parallax effect also offers a more mundane explanation of the Go Fast video, West contends. Andrew Dyer, San Diego Union-Tribune, 29 May 2021 And yet, no matter how acute your vision was, nobody had ever observed a parallax for any of the stars in the sky. Ethan Siegel, Forbes, 10 Mar. 2021 See More Word History
Etymology
Middle French parallaxe, from Greek parallaxis, from parallassein to change, from para- + allassein to change, from allos other
First Known Use
1580, in the meaning defined above
Medical Definition
parallax
noun
par·al·lax ˈpar-ə-ˌlaks
: 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
motion parallax governs the way objects appear to move when the eyes or head are shifted Edmund Andrews
Edmund Andrews