Origin: 1300–50; (n.) ME deces < OF < L dēcessus departure, death, equiv. to dēced-, var. s. of dēcēdere to go away (dē-de-+ cēdere to go; see cede) + -tus suffix of v. action, with dt > s; (v.) late ME decesen, deriv. of the n.
de·cease (dĭ-sēs') intr.v.
de·ceased, de·ceas·ing, de·ceas·es To die. n. The act of dying; death.
[Middle English decesen, from deces, death, from Old French, from Latin dēcessus, departure, death, from past participle of dēcēdere, to depart, die : dē-, de- + cēdere, to go; see ked- in Indo-European roots.]
c.1330, from Fr. deces, from L. decessus "death," lit. "departure" (euphemism for mors), from pp. stem of decedere "die," from de- "away" + cedere "go" (see cede). Still used with a tinge of euphemism.