Other forms: deceases
Decease is a person's death, in legal use. Upon his decease, the date of decease, prior to decease.
It appears almost only in wills, insurance and official forms, where the plainer word is avoided. The participle deceased is far commoner and is the standard term for a dead person in any legal document.
1noundeceaseA person's death, in legal use.
“On the decease of the owner, the house will pass to his eldest son.”
decease is a death.
Latin decessus means a departure, from decedere, to go away.
Latin
dēcessus — departure
Old French
deces
English, today
decease
From Old French deces (Modern French décès), from Latin dēcessus (“departure”).
Etymology from Wiktionary, CC BY-SA