Subsequent to, or influenced or affected by, the work of Albert Einstein; involving or relating to concepts developed after or building on Einstein's theories of relativity.
Origin
1930s. From post- + Einsteinian.
Definition of post-Einsteinian in US English:
post-Einsteinian
adjectiveˌpəʊstʌɪnˈstʌɪnɪən
Subsequent to, or influenced or affected by, the work of Albert Einstein; involving or relating to concepts developed after or building on Einstein's theories of relativity.