The Collaborative International Dictionary of English v.0.48:

Coronis \Co*ro"nis\ (k?-r?"n?s), n. [Gr. korwni`s anything
   curved. See Cornice.]
   1. In Greek grammar, a sign ['] sometimes placed over a
      contracted syllable. --W. W. Goodwin.
      [1913 Webster]

   2. The curved line or flourish at the end of a book or
      chapter; hence, the end. [R.] --Bp. Hacket.
      [1913 Webster]