Sheet music is a type of music notation in which the sound of music is represented by written symbols and signs. The term "sheet" is used to distinguish written music, regardless of medium, from audio presentations of sound, such as those found on records or tapes. Sheet music is a way of notating sound to quickly learn a piece of music. Sheet music necessitates the ability to read music notation, which is a subset of literacy. By simply looking at the sheet music, a musician can perform a piece of music they have never heard before. When this happens for the first time, it is referred to as sight reading. Although sheet music is most commonly associated with learning new music, it can also serve as a visual record of previously recorded music. Staff-note and tablature transcriptions of such music make it readable for study, analysis, and performance. This is done not only with traditional folk songs, but also with sound recordings of rock and jazz musicians improvising.