The Collaborative International Dictionary of English v.0.48:

Coroner \Cor"o*ner\ (k?r"?-n?r), n. [From OE. coronen to crown,
   OF. coroner, fr. L. coronare, fr. corona crown. Formed as a
   translation of LL. coronator coroner, fr. L. corona crown,
   the coroner having been originally a prosecuting officer of
   the crown. See Crown.]
   An officer of the peace whose principal duty is to inquire,
   with the help of a jury, into the cause of any violent,
   sudden or mysterious death, or death in prison, usually on
   sight of the body and at the place where the death occurred.
   [In England formerly also written and pronounced crowner.]
   [1913 Webster]

   Note: In some of the United States the office of coroner is
         abolished, that of medical examiner taking its place.
         [1913 Webster]

   Coroner's inquest. See under Inquest.
      [1913 Webster]

WordNet (r) 3.0 (2006):

coroner
    n 1: a public official who investigates by inquest any death not
         due to natural causes [syn: coroner, medical examiner]