A piano trio is a musical ensemble consisting of three instruments: a piano, a violin, and a cello. This combination allows for a rich blend of sounds, with the piano providing harmony and rhythm, while the violin and cello contribute melody and depth. Piano trios are popular in classical music and often feature in chamber music settings. Composers like Ludwig van Beethoven and Franz Schubert have written notable works for piano trio, showcasing the unique interplay between the instruments. The format allows for both collaborative and solo passages, making it a versatile choice for musicians and composers alike.