The cornamuse is a double reed instrument from the Renaissance era. It is similar to the crumhorn because both have a windcap over the reed and a cylindrical shape. The only information about the cornamuse comes from descriptions and comments by Michael Praetorius in Syntagma musicum II, published in 1619. Since Praetorius's paragraph is the only clear description of the cornamuse and no physical examples or pictures from that time have been found, all attempts to rebuild the instrument are based on educated guesses.

In German, Praetorius wrote: "The cornamuse are similar to/and do not have a double, but rather a single tube (bore)/like the bassanelli. […] but closed at the bottom and with some small holes on the sides through which the sound escapes. In sound, they are very similar to the crumhorns, but they are quieter, more pleasant, and very soft." This description shows that the cornamuse had a single tube, unlike other instruments of the time, such as the sordun, kortholt, and curtal, which had double tubes. Another clue about its appearance comes from Praetorius's description of the schryari: "They…are nearly the same as the cornamuse in size and appearance."

The name "cornamuse" should not be confused with "cornemuse," which is the French word for bagpipes.