secession n.

word-forming element in words of Latin origin, "apart, away," from Latin se-, collateral form of sed- "without, apart, aside," probably originally "by one's self, on one's own," and related to sed, Latin reflexive pronoun (accusative and ablative), from PIE *sed-, extended form of root *s(w)e-, pronoun of the third person and reflexive (source also of German sich; see idiom).

Proto-Indo-European root meaning "to go, yield."

It forms all or part of: abscess; accede; access; ancestor; antecede; antecedent; cease; cede; cession; concede; decease; exceed; excess; incessant; intercede; necessary; precede; predecessor; proceed; recede; recess; recession; secede; secession; succeed; success.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit sedhati "to drive, chase away;" Avestan apa-had- "turn aside, step aside;" Latin cedere "to yield, give place; to give up some right or property," originally "to go from, proceed, leave;" Old Church Slavonic chodu "a walking, going," choditi "to go."

1860, first in a U.S. context, "one who takes part in or justifies the attempt by the Southern states to withdraw from the union," from secession + -ist. Colloquial short form secesh, noun and adjective, is attested from 1861. The earlier noun had been seceder (1755), but this had religious overtones, especially (with capital s-) in reference to Scottish Church history (see secede). Related: Secessionism.