Source : Webster's Revised Unabridged Dictionary (1913)

Decease \De*cease"\, n. [OE. deses, deces, F. d['e]c[`e]s, fr.
   L. decessus departure, death, fr. decedere to depart, die;
   de- + cedere to withdraw. See {Cease}, {Cede}.]
   Departure, especially departure from this life; death.

         His decease, which he should accomplish at Jerusalem.
                                                  --Luke ix. 31.

         And I, the whilst you mourn for his decease, Will with
         my mourning plaints your plaint increase. --Spenser.

   Syn: Death; departure; dissolution; demise; release. See
        {Death}.

Decease \De*cease"\, v. i. [imp. & p. p. {Deceased}; p. pr. &
   vb. n. {Deceasing}.]
   To depart from this life; to die; to pass away.

         She's dead, deceased, she's dead.        --Shak.

         When our summers have deceased.          --Tennyson.

         Inasmuch as he carries the malignity and the lie with
         him, he so far deceases from nature.     --Emerson.

Source : WordNet®

decease
     n : the event of dying or departure from life; "her death came
         as a terrible shock"; "upon your decease the capital will
         pass to your grandchildren" [syn: {death}] [ant: {birth}]
     v : pass from physical life and lose all all bodily attributes
         and functions necessary to sustain life; "She died from
         cancer"; "They children perished in the fire"; "The
         patient went peacefully" [syn: {die}, {perish}, {go}, {exit},
          {pass away}, {expire}, {pass}] [ant: {be born}]