The medium female singing voice in opera and non-classical music (although in the choir, the mezzo-soprano and the contralto are lumped together as altos). The mezzo-soprano has a range of two octaves from A3 (below middle C) to A5 (just two notes short of high C). This is the most common female voice.

Situated between the soprano and contralto, the mezzo-soprano typically plays supporting roles (mothers, maidservants, friends of the heroine) as well as villainous women like the femme fatale (the saying among mezzo-sopranos and contraltos is that they play "witches, britches, and bitches").

Many pop singers are mezzo-sopranos, although the vocal subcategories used in opera are not applied to them. Examples include Madonna, Beyonce, Patti Lupone, Ethel Merman, Tori Amos, Mary J. Blige, Aretha Franklin, Jennifer Hudson, Whitney Houston (since the mid-1990s), Enya, Janet Jackson, Barbra Streisand, Alanis Morissette, and Sarah McLachlan.
Based on vocal weight/voice type, mezzo-sopranos re divided into three subtypes:

Coloratura mezzo-soprano: Light, flexible, pure, very agile and sings very ornate passages (very rare voice). Examples include Cecilia Bartoli, Marilyn Horne, and Jennifer Larmore, and Vivica Genaux.

Lyric mezzo-soprano: Light, mellow, strong and often plays trouser roles (a woman who plays boys and adolescent males) as well as perfectly feminine characters. Examples include Frederica von Stade, Anne Sophie von Otter, Tatiana Troyanos, and Katherine Jenkins.

Dramatic mezzo-soprano: Powerful, rich, warm and with a stronger (and seductive) lower range than a soprano, she is reserved for the roles of villains (temptresses, femmes fatales, witches) as well as mothers and friends of the soprano. Examples include Grace Bumbry, Dolora Zajick, Denyce Graves, Olga Borodina, and Viorica Cortez.

Mezzo-sopranos can't sing high notes as easily as sopranos (they sound appropriately wild and crazed when they do), but they get their revenge by playing some of the spiciest roles ever.
by Lorelili July 7, 2011
The medium womon's singing voice. Plays evil characters; seductresses, vamps, occasionally teenage boys...
Listen to this... the lengendary mezzo-soprano character of Carmen... crooning her seductive Habañera...
by Sam October 27, 2004
What most female singer are. Seriously.
If one is a soprano, they can hit A 5 with no trouble at all.
If one is a full-soprano, they can hit C 5 with no trouble at all.
If one is a contralto, they can hit C2 with no trouble at all.
If you can't hit any of the above notes, you are a mezzo-soprano
by Persephone~ June 5, 2009