parallax

Etymology

From Middle French parallaxe, from Ancient Greek παράλλαξις (parállaxis, “alteration”) from παραλλάσσω (parallássō, “to cause to alternate”) from ἀλλάσσω (allássō, “to alter”) from ἄλλος (állos, “other”).

noun

1. An apparent shift in the position of two stationary objects relative to each other as viewed by an observer, due to a change in observer position.
   […] Heliocentrick places, to which the Parallaxes being applied, give the Geocentrick. 1685, J. Flamsteed, Philosophical Transactions, XV, p. 1217
   Planes farther back on the z-axis scroll more slowly than those in front of them, producing a parallax effect. Early games with parallax scrolling tended to have their action taking place all in the forefront plane […] 2008, Bernard Perron, Mark J. P. Wolf, The Video Game Theory Reader 2, page 157
2. (astronomy) The angle of seeing of the astronomical unit.

verb

1. (transitive) To measure (a distance) based on parallax observations.
2. (animation) To produce an illusion of levels of distance by shifting layers at different rates.