Pronunciation: (rel"u-tu-vis'tik), [key]
1. of or pertaining to relativity or relativism.
a. subject to the special or the general theory of relativity.
b. (of a velocity) having a magnitude that is a significant fraction of the speed of light.
c. (of a particle) having a relativistic velocity: radiation from relativistic electrons.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.