What is a mezzo-soprano?
The mezzo-soprano or mezzo is the second highest female voice type.
In a large choir, a mezzo-soprano will usually sing along with the sopranos, not the altos, with the vocal part 'Soprano II' or 'Soprano 2'. If the sopranos split in half, a mezzo will sing the lower melody as typically, a mezzo vocal timbre is darker than the soprano.
In opera mezzo-sopranos most often hold supporting roles and 'trouser roles' – in other words, male roles sung by a female singer. There are many exceptions and some of the more famous ones include the characters of Carmen in the opera with the same name and Rosina in The Barber of Seville, where the prima donna is a mezzo-soprano.
A typical mezzo can vocalize from G3 to A5, though voices are highly variable. Some mezzos can't sing as high as this and some can sing as high as a typical soprano.