the apparent displacement or the difference in apparent direction of an object as seen from two different points not on the same straight line
in astronomy, the difference in direction of a planet, star, or other celestial body as measured from two points on the earth or on the earth's orbit round the sun
parallactic /-ʹlaktik/ adj
[early French parallaxe from Greek parallaxis, from parallassein to change, alternate, ultimately from para-1 + allos other]