How is a piano trio different from a string trio?

In the context of chamber music, the primary difference between a string trio and a piano trio lies in their instrumentation and the resulting musical texture.

• String Trio: This ensemble is composed strictly of string instruments, typically a violin, a viola, and a cello. Some variations, such as those by Joseph Haydn, utilize two violins and a cello.1
• Piano Trio: This ensemble consists of a piano, a violin, and a cello. Because the piano is a keyboard instrument capable of playing multiple notes simultaneously, the piano trio allows for a fuller, more varied harmonic texture compared to the string trio.1

While the string trio emerged as a distinct chamber genre in the Classical period, the piano trio gained prominence as the piano became more widely available in the 18th century, eventually becoming a major medium for composers from Haydn and Beethoven to the Romantic era and beyond.1