The alphorn or alpenhorn or alpine horn is a labrophone, consisting of a straight several-meter-long wooden natural horn of conical bore, with a wooden cup-shaped mouthpiece. Traditionally the Alphorn was made of one single piece, or two parts at most, of the wood of a red pine tree. Sometimes the trees would bend from the weight of snow in winter, and this caused them to have the larger and bent mouthpiece at their ends. Modern Alphorns are sometimes made from three distinct parts that can be attached together: this is to make them easier to transport by car, or even to carry them by hand, and today they are more frequently made from the wood of a spruce tree or fir tree. The alphorn is used by mountain dwellers in the Swiss Alps. Similar wooden horns were used for communication in most mountainous regions of Europe, from the Alps to the Carpathians. Alphorns are today used as musical instruments.

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'.