Étude
From the Simple English Wikipedia, the free encyclopedia that anyone can change
Étude is the French word for study. An étude (or “study”) is a short piece of music written to help the player to become a better player. Composers such as the pianist Carl Czerny and the violinist Otakar Ševčik wrote lots of studies. Each one concentrates on a technical problem: fast scale-like passages, arpeggios, wide leaps, chords or, for string players, different ways of bowing.
Frédéric Chopin wrote two sets of études which are not just extremely good for developing piano technique but also wonderful music. Franz Liszt also wrote some very difficult and very beautiful études.