Etymology

Noun

1. An element of decoration.
   • 1919: P. G. Wodehouse, My Man Jeeves

     ...I'm a bit short on brain myself; the old bean would appear to have been constructed more for ornament than for use

2. A Christmas tree decoration
3. A musical flourish that are unnecessary to the overall melodic or harmonic line, but serve to decorate or "ornament" that line.

Verb

1. To decorate.

   We will ornament the windows with trim to make the room seem brighter.

2. To add to.

   The editor ornamented his plain writing, making it fancier but less clear.