epochismn.

/ˈɛpəkɪz(ə)m/Etymology: formed as epoché n. + -ism suffix.
the world > time > period > [noun] > dividing time into periods
1865 No. 1970. 140/1 Chronological epochism.
This entry has not yet been fully updated (first published 1891; most recently modified version published online March 2018).