Dictionary
yo
Pronunciation: (yō), [key]—
interj.
1. (used as an exclamation to get someone's attention, express excitement, greet someone, etc.)
2. here; present: used esp. in answer to a roll call.
y.o.
year old; years old.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.