Vocals are any sound produced by the throat, and can including speaking, singing, screaming, shouting, whispering, grunting, screeching, squealing, etc.
Vocals are usually classified by their intended effect, speaking and singing being the most common. Others may be more common in other genres. Some vocal sounds may be undesirable in one genre, where as they will be common or popular in another.
Vocals can also be labeled as male or female, which is used as a rough label for gauging the frequency range and tonal characteristics of the voice.
Singing vocals may be further categorized by range, which gives even more information about their sonic content. The following are the most common, keeping in mind that C4 is middle C.
Soprano: C4 - C6
Alto: G3 - F5
Tenor: C3 - C5
Baritone: F2 - F4
Bass: E2 - E4