decession (n.)

c. 1400, decessioun, "departure, separation;" c. 1600, "decrease from a standard, diminution," from Latin decessionem(nominative decessio) "a going away, departure," noun of action from past-participle stem of decedere "to go down, depart," from de "away" (see de-) + cedere "to go" (from PIE root *ked- "to go, yield").