Yo - Is a greeting-e.g.(sup yo?) And a word to begin or end a sentence. common with people in the northeastern U.S. New York Connecticut Mass. was created in the 80's by break dancers original, b boy's, and m.c.'s it is one of hip hops most common and original slang words that has been adopted by the rest of the united states and other countries but only sounds right comin from east coast dialect in which it originated, but we are proud to to have so many imitaters - Peace Yo!