parallax(redirected from homonymous parallax)
Also found in: Thesaurus, Medical, Encyclopedia.
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 toward the object.
[French parallaxe, from Greek parallaxis, from parallassein, to change : para-, among; see para-1 + allassein, to exchange (from allos, other; see al- in Indo-European roots).]
par′al·lac′tic (-lăk′tĭk) adj.
1. (General Physics) an apparent change in the position of an object resulting from a change in position of the observer
2. (Astronomy) 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
[C17: via French from New Latin parallaxis, from Greek: change, from parallassein to change, from para-1 + allassein to alter]
1. the apparent displacement of an observed object due to a change in the position of the observer.
2. the apparent angular displacement of a celestial body due to its being observed from the surface instead of from the center of the earth or due to its being observed from the earth instead of from the sun.
3. 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.
[1585–95; < Greek parállaxis change =parallak- (s. of parallássein to cause to alternate =para- para-1 + allássein to vary, akin to állos other) + -sis -sis]
par`al•lac′tic (-ˈlæk tɪk) adj.
Viewed from point A, a nearby star appears to occupy position a against a background of more distant stars. Six months later, from position B, the star appears to occupy position b.
An apparent change in the position of an object, such as a star, caused by a change in the observer's position that provides a new line of sight. 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.
In photography, the apparent displacement of the position of an object in relation to a reference point, due to a change in the point of observation.
Switch to new thesaurus
|Noun||1.||parallax - the apparent displacement of an object as seen from two different points that are not on a line with the object|
optical phenomenon - a physical phenomenon related to or involving light
annual parallax, heliocentric parallax - the parallax of a celestial body using two points in the earth's orbit around the sun as the baseline