SATB is an initialism that describes the scoring of compositions for choirs and choirs of instruments. The initials stand for the voice types: S for soprano, A for alto, T for tenor, and B for bass. This acronym is commonly used to denote the four most common types of voices in a choir. Each voice type brings its own set of characteristics, such as range, timbre, tessitura, and passaggio. SATB groupings are defined by a mixture of these characteristics, and they are particularly useful for voices that have fully matured and are pursuing classical arrangements. The rules of voice leading apply to SATB notations, and the abbreviation is also used by publishers to describe different scorings for soloists and choirs other than four-part harmony. In a broader sense, choirs of instruments can also be described by the abbreviation SATB, often for members of the same family of instruments, such as consorts of recorders, viola da gamba, saxophones, and trombones. Therefore, SATB is a fundamental concept in choral and instrumental music, representing the standard make-up of a chorus with mixed male and female voices.