Yo definitions

Used as a greeting or to attract someone's attention.
interjection
22
3
Used to express emphasis.

Today's my birthday, yo.

interjection
17
2
Used variously to attract attention, greet someone, introduce or emphasize a remark, etc.
interjection
8
1
abbreviation
6
2
(African American Vernacular) Contraction of you and are.

Yo a fool.

contraction
6
3
(slang) A greeting similar to hi.

Yo Paulie! How's it going?

interjection
5
1
Yogyakarta, a special region of Indonesia.
abbreviation
3
1
(slang) An interjection similar to hey.

Yo, check this out!

interjection
0
1
(military slang) Present! Here!

Sergeant: Smith? Private Smith: Yo!

interjection
0
1
(colloquial) Shortened form of your.

Yo sandwich only has bacon in it. Want some ketchup on that?

pronoun
0
1
(Baltimore) Third-person singular, familiar.

Yo was tuckin' in his shirt! (Stotko and Troyer 2007)

pronoun
0
1
Abbreviation of year/years old.
noun
0
1

Origin of yo

From Middle English yo, io, ȝo, yeo, yaw, variant forms of Middle English ya, ye (“yes, yea"), from Old English Ä¡Ä“a (“yes, yea"). Compare Danish, Swedish, Norwegian jo (“yes"). More at yea.