Pythagoreanism

noun

Py·​thag·​o·​re·​an·​ism pə-ˌtha-gə-ˈrē-ə-ˌni-zəm 

(ˌ)pī-

: the doctrines and theories of Pythagoras and the Pythagoreans who developed some basic principles of mathematics and astronomy, originated the doctrine of the harmony of the spheres, and believed in metempsychosis, the eternal recurrence of things, and the mystical significance of numbers

Word History

First Known Use

circa 1727, in the meaning defined above