Musical instruments with O

• Organ

  Keyboard instrument, air through pipes makes big churchy sounds.

• Ocarina

  Small wind instrument, whistle-like sound

• Oud

  Middle Eastern string instrument, plucked

• Orange guitar

  A guitar is an instrument, orange is just its color.

• Old guitar
• Opera voice

  Human voice used like an instrument in opera singing.

• orange drums

  Drums are instruments; orange is just their color.

• Org

  Short for organ, keyboard wind instrument in music

• OBOE

  Oboe, double‑reed woodwind, key in orchestras

The words in the list Musical instruments with O come from players of the word game City, Country, River.