The Hornbostel-Sachs classification is a system used to categorize musical instruments based on how they produce sound, originally developed by Erich Moritz von Hornbostel and Curt Sachs in 1914. It divides instruments into five primary categories: idiophones, membranophones, chordophones, aerophones, and later, electrophones, facilitating a universal framework for the study of ethnomusicology and organology.