英语词源字典 - 在线词源网站

secede (v.)[secede 词源字典]: 1702, "to leave one's companions," from Latin secedere "go away, withdraw, separate; rebel, revolt" (see secession). Sense of "to withdraw from a political or religious alliance of union" is recorded from 1755, originally especially in reference to the Church of Scotland. Related: Seceded; seceding; seceder.[secede etymology, secede origin, 英语词源]
secession (n.): 1530s, from Latin secessionem (nominative secessio) "a withdrawal, separation; political withdrawal, insurrection, schism," noun of action from past participle stem of secedere "secede," from se- "apart" (see secret) + cedere "to go" (see cede). Originally in a Roman historical context, "temporary migration of plebeians from the city to compel patricians to address their grievances;" modern use in reference to religious or political unions dates from 1650s.
secessionist (n.): 1860, first recorded in U.S. context, from secession + -ist (colloquial short form secesh, noun and adjective, is attested from 1861); the earlier noun had been seceder, but this had religious overtones, especially in reference to Scottish Church history.