Coroner
Middle English: from Anglo-Norman French coruner, from corune ‘a crown’ (see crown); reflecting the Latin title custos placitorum coronae ‘guardian of the pleas of the Crown’.
wiktionary
From Middle English coroner, from Old French curuner, from Medieval Latin custos placitorum coronae(“guardian of the crown's pleas”). The function was originally to protect royal properties.
etymonline
coroner (n.)
title of a county or municipal officer with certain duties, mid-14c. (mid-13c. as a surname), corouner, from Anglo-French curuner, from Anglo-Latin custos placitorum coronae (late 12c.), originally the title of the officer with the duty of protecting the private property of the royal family, from Latin corona, literally "crown" (see crown (n.)).
In the Middle English period an elected county or borough officer charged with the supervision of pleas of the Crown and the administration of criminal justice. The duties of the office gradually narrowed and by 17c. the chief function was to determine the cause of death in cases not obviously natural.
