What's the difference between i.e. and e.g.?
in music, originally a study or technical exercise, later a complete and musically intelligible composition exploring a particular technical problem in an esthetically satisfying manner. Although a number of didactic pieces date from earlier times, including vocal solfeggi and keyboard works (Domenico Scarlatti's Esercizi per gravicembalo), the etude came into its own only in the late 18th and early 19th centuries with collections published by the virtuoso pianist Muzio Clementi (especially his Gradus ad Parnassum, 1817), emulated by other pianist-composers, especially Karl Czerny. With the 27 piano etudes by Frederic Chopin (Opus 10, 1833; Opus 25, 1837), the etude became a composition of considerable musical interest apart from its merit as a technical study. Many of the Transcendental Etudes by piano virtuoso Franz Liszt feature descriptive titles (e.g., La campanella, or "The Little Bell"). Claude Debussy's Douze Etudes (1915; 12 Etudes) and Gyorgy Ligeti's Etudes for Piano (Book 1, 1985; Book 2, 1988-94) are notable later examples.