In modern music, wind music generally refers to any music played by wind instruments and produced via the breath of the player. More than one category of wind music exists, however. Less commonly, wind music refers to music actually produced by the wind of the Earth, not the breath.
Strictly, instruments capable of producing this type of music include only "aerophone" instruments such as flutes, oboes, clarinets and bassoons, as well as saxophones. These instruments produce sound by causing a column of air to vibrate. Brass labrosones, or "lip vibrated" instruments such as trumpets and french horns, often are classed as a separate family from wind instruments. Technically, labrosones are a subcategory of aerophone, because players cannot cause their lips to vibrate and produce a tone on the instrument without using their breath. Thus, brass instruments sometimes perform with other woodwind instruments, such as the french horn does in a woodwind quintet.
In defining wind music, musicians consider the primary instruments, not the accompaniment. For example, if a composer writes a flute solo with string quartet accompaniment, the flute is the instrument highlighted for virtuosity and tone. The work thus would be classed as wind music despite the presence of the strings, which are not aerophones.
Wind music produced with the breath falls into two large categories: concert and chamber. Concert music requires too many players to be performed well in small rooms. Probably the best example of groups in this category are wind bands, sometimes called wind ensembles, which can have anywhere from 25 to 100 performers and who may march, depending on the band type. Chamber music usually involves less than 10 players. For chamber wind music, solos, duets, trios, quartets and quintets are the most common sizes, although music for groups such as octets and double quintets exist.
Performing wind music requires players to prepare their instruments in ways not required for non-aerophone instruments. The primary consideration is that the instrument usually is much cooler than the breath the player uses, especially if the performance area has extreme air conditioning. Heat makes aerophones go sharp, so before a performance, players literally warm their instruments by blowing into it without the reed or holding it in their hands, preferably for at least five minutes. This helps prevent pitch from changing dramatically when playing, as well as damage such as cracks from the rapid temperature shift. "Warm up" for non-aerophones is more about getting the muscles of the body, particularly of the fingers and mouth, ready for the movements required in performance.
Another consideration for wind players is sustain of pitch. Some players are capable of techniques such as circular breathing, but typically, players can sustain notes only so long as they can continue to push air from their lungs. This isn't the case with non-aerophone instruments. A string player, for example, can sustain a pitch for an entire pitch if necessary, although they must change bow direction to keep the sound going. Composers have to take this into consideration when writing music and check that phrases are not constructed in ways that prevent taking a good breath.
When referring to music produced without the breath, wind music refers to sounds made by instruments such as the Aeolian harp or even wind chimes. Because these instruments rely on the wind for tonal production, their sounds are unpredictable and aleotoric, meaning they are left to chance. There really is no way to compose this type of wind music as a result, although recordings of the sounds produced could be transcribed and written down if desired.