Parallax is when an object appears to change its position because the person or instrument observing it has changed their position.
[technical]
parallax in British English
(ˈpærəˌlæks)
noun
1.
an apparent change in the position of an object resulting from a change in position of the observer
2. 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
parallactic (ˌpærəˈlæktɪk)
adjective
parallactically (ˌparalˈlactically)
adverb
Word origin
C17: via French from New Latin parallaxis, from Greek: change, from parallassein to change, from para-1 + allassein to alter
parallax in American English
(ˈpærəˌlæks)
noun
1.
the apparent change in the position of an object resulting from the change in thedirection or position from which it is viewed
2.
a.
the amount of angular degree of such change: the parallax of an object may be used in determining its distance from the observer because smaller angles indicate greater distance
b. Astronomy
the apparent difference in the position of a celestial object with reference to a fixed background when viewed from two distant locations having a triangulated base line equal to the radius of the earth (diurnal parallax or geocentric parallax) or equal to the radius of the earth's orbit (annual parallax or heliocentric parallax)
3.
the difference between the actual view covered by a camera lens and the apparent view seen through the viewfinder: this may be significant when the object is close to the camera
Derived forms
parallactic (ˌparalˈlactic) (ˈpærəˈlæktɪk)
adjective
Word origin
Fr parallaxe < Gr parallaxis < parallassein, to vary, decline, wander < para-, para-1 + allassein, to change < allos, other: see else