RELATIVISTIC
relativistic
(adjective) relating or subject to the special or the general theory of relativity; “relativistic quantum mechanics”; “relativistic increase in mass”; “radiation from relativistic particles”
relativistic
(adjective) of or relating to the philosophical doctrine of relativism
Source: WordNet® 3.1
Etymology
Adjective
relativistic (comparative more relativistic, superlative most relativistic)
(physics) Of or relating to relativity.
(physics) At or near the speed of light.
(philosophy) Of or relating to relativism.
Source: Wiktionary