The word avlos is Greek and its main meaning is pipe, or air vent. The earliest signs of the existence of the avlos in Greece date back to the end of the 8th century B.C.
The avlos was most probably associated with the worship of Dionysus, rather than that of Apollo the lyre bieing the instrument used for the worship of the latter God. It is for this reason that the avlos was considered inappropriate for the education of youth. Many writers and philosophers of the archaic period advised against the use of the avlos. Plato, the philosopher in his book The Republic (3rd volume, 399d) holds the avli in low regard describing them as instruments that have the power to entrance the listener instilling a feeling of delirium that leads to insinuations that he/she was in a terrible need of spiritual purification. (West, page 115). Hence Homer avoids any mention of the avlos despite the fact that it's presence is very obvious in a multitude of public ceremonies in later years: victory songs, dirges, sacrifices, military marches, rowing exercises, festive dances.
Aristoxenos, the musical theorist, wrote a monograph (¶ÂÚ› ∆Ú›ÛÂˆ˜ ÙˆÓ A˘ÏÒÓ) relating to the opening and structure of the holes in the avlos in which he maintained that there were five kinds of avlos: parthenii, kitharistirii, telii and hypertelii. It is safe to assume that these adjectives correspond to the terms, Soprano, Mezzo Soprano, Contralto, Tenor, Baritone. There are a multitude of other terms defining different forms of the avlos that are referred to in classical literature before the time of Aristotle and Aristoxenos (imiopus, vomvyx, playiavlos, mesokopos, pithikos, chorodiakos, tragic, theatrical, hippoforvos, etc).
There were forms of the avlos that had the shape of a simple pipe, others with a single or double-reed, made of different materials such as straw, reed, wood, bone, metal.