The flugelhorn, also spelled fluegelhorn, flugel horn, or flügelhorn, is a brass instrument that resembles the trumpet and cornet but has a wider, more conical bore. Like trumpets and cornets, most flugelhorns are pitched in B♭, though some are in C. It is a type of valved bugle, developed in Germany in the early 19th century from a traditional English valveless bugle. The first version of a valved bugle was sold by Heinrich Stölzel in Berlin in 1828. The valved bugle provided Adolphe Sax with the inspiration for his B♭ soprano (contralto) saxhorns, on which the modern-day flugelhorn is modelled.

A brass instrument is a musical instrument that produces sound by sympathetic vibration of air in a tubular resonator in sympathy with the vibration of the player's lips. Brass instruments are also called labrosones or labrophones, from Latin and Greek elements meaning 'lip' and 'sound'.