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-1 in the Appendix of Indo-European roots).]
par′al·lactic (-lăktĭk) adj.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.