Yo

[Gregory]

[Substitution] for [someones] [name].

[Sommer]

Another [Way] of [saying] hey or [hi]

[Renato]

A greeting, can also mean a Woman friend or [associate] that isnt [intimate] which in plural is [Yos]

[Kai]

In the English language, yo has become a common interjection that originated decades ago in the Philadelphia region. It is often interchangeable with the word hey, as in Yo, whats up? or, Yo! Wait for me! While the word can also stand alone as a greeting, like the word hey, it also has a wide range of meanings that depend on the tone, context, and situation in which it is used. (see examples)
In more recent times the word has spread into hip-hop or gangsta culture. A parody of such usage forms the basis for a comic exchange between the animated characters played by Robert DeNiro and [Martin Scorsese] ([Shark Tale], 2004), which can be viewed here (http://yoism.org/[index.php]?id=[YoST]/).
Members of this later cultural scene may claim its origin as theirs. The words origin, however, clearly predates these recent uses, as is evidenced by the words of [Rocky Balboa] (played by Sylvester Stallone)
Yo, Adrienne, its me, Rocky... Rocky Balboa (Rocky, 1976)
Yo, Adrienne. We did it! Rocky Balboa (Rocky II, 1979)

[Sarah]

Interchangeable with the [words] [huh] or what or [hey]

[PussyCat]

A word of [greeting] that sounds [orgasmic] when [Eminem] says it.

[Lizzy Liz]

[Slang] [for you].

[Vania]

[GANGSTA] SLANG
In that case yo is a short form of the [possessive] [pronoun] your.