Soprano
The soprano part is typically the highest vocal part and is sung by female voices. Sopranos have a bright and clear tone and are responsible for carrying the melody in many choral pieces.
Alto
The alto part is the second-highest vocal part and is also sung by female voices. Altos have a slightly lower and mellower tone than sopranos and often provide a supporting harmony to the melody.
Tenor
The tenor part is the highest male vocal part and is responsible for singing the second highest melody. Tenors typically have a rich and full tone.
Bass
The bass part is the lowest vocal part and is sung by male voices. Basses provide the foundation and harmonic support for the entire choir and often sing the lowest notes in a choral piece.
SATB is the most common vocal configuration in choral music, but there are many other variations. Some choirs may have additional voice parts such as mezzo-soprano, baritone, or countertenor, while others may have multiple voice parts for each section (e.g., first and second sopranos, first and second altos, etc.).
Choral music that is written in SATB format can be performed by a wide variety of ensembles, including choirs, glee clubs, and vocal groups. SATB music can be found in a variety of genres, including classical, contemporary, sacred, and secular music.