An orchestra is a large musical ensemble typically composed of strings, brass, woodwinds, and percussion instruments. The three instruments mentioned in the crossword solutions are all part of the orchestra. Oboes are a type of double-reed woodwind instrument with a distinctive sound. They have five letters in their name. Brass instruments are a class of wind instruments that produce sound by vibrating the player's lips against a cup-shaped mouthpiece. They have seven letters in their name. Flutes are a type of woodwind instrument that produces sound when air is blown across an opening. They have six letters in their name.