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