Soprano

The highest of the female voice types, the soprano has always had a place of prominence in the hierarchy of vocal types. In the operatic drama, the soprano is almost always the heroine or protagonist of an opera, since a high, bright sound can suggest youth, innocence, and virtue.

Example: O mio babbino caro ("Oh my dear daddy") is an aria from the opera Gianni Schicchi (1918) by Giacomo Puccini.

Mezzo-soprano

A mezzo-soprano, or mezzo, has a voice lower then a soprano’s but higher than a contralto’s. Throughout opera history the mezzo has been used to convey many different types of characters: everything from boys or young men (so-called trouser or pants roles), to mothers or mother-types, seductive heroines, and villainesses.

Example: The "Habanera" is an aria from the opera Carmen by Georges Bizet.

Tenor

The highest of the male voices, the tenor is frequently the hero or protagonist of an opera.

Example: "La donna è mobile" ("Woman is fickle") is the cynical Duke of Mantua's canazone from Giuseppe Verdi's opera Rigoletto (1851).

Baritone

The baritone is the most common male voice, lower in range than the tenor and with a darker tone. In comic opera, the baritone is often the ringleader of the hijinks, but in tragic opera, he is often the villain.

Example: Largo al factotum ("Make way for the factotum") is an aria from The Barber of Seville by Gioacchino Rossini, sung at the first entrance of the title character; the repeated "Figaro"s before the final patter section are an icon in popular culture of operatic singing. The term "factotum" refers to a general servant and comes from the Latin where it literally means "do everything."

Bass

The lowest and darkest of the male voices. Low voices often suggest age and wisdom or evil characters in serious opera, but in comic opera they are often used for old characters who are foolish or laughable.

Example: The character of Osmin from The Abduction from the Seraglio by Mozart.

Rabbit 

of 

Seville