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2.
an exclamation to proclaim suprise, or astonishment; a formal greeting; expressing praise at an action.
"Yo, last night, she was the shite..."
"Fo real? you hit that huh! HIYO!"
or
"Yo, Blake dunked last night!"
"HIYO!"
by DJ D February 02, 2003
 
1.
An expression originally coined by Ed McMahon during his side kick status on Johnny Carson's Tonight Show.

These days, it now is used to follow a witty response or comment to insult someone or "zing" them (See: Zing).
"Dad said I should be over 6 ft tall in a few years". "Yeah, but he also said you were going to be intelligent, but that never happened....HIYOOOOOOO".
by Debasser! August 23, 2010
 
3.
An exclamation used in situations where one person insults another or says something rude/crude/twisted.
Person 1: You skank!
Group: Hi-yo!
by Maxie/Py August 22, 2005
 
4.
Hiyo(Ih-Yoh; noun): The small short and sweet combination of the salutations of "Hi" , "Yo" , "Hey" compiled and shortened to a short and sweet, yet slightly annoying new salutation. Makes it easier to say "Hey" when you could just scream "HIIIIIIIIIYOOOOOH!!" and annoys some people.

Other versions of "Hiyo":
"Heyo" , "Heya" , "Hiya" ,"Hoyo" etc.
"Hiyo is just a more complicated way of saying Hi or Hey, Or Yo.That easy!"
by Chachoregard September 03, 2005
 
5.
mmmmmmhiyo or hhhhhiyo - elongated for maximum hiyo-ness..
"blake threw one down on wethersfield? HHHIYO! that must ha been the shite!"
by you dead wrong February 05, 2003
 
6.
An exclamative(exclamatory) expression with roots to the Indian "hiyo hiyo" chant. Was used in the Lone Rangers comics and shows. And now decades later was used in music and movies as well. Although the interpretation remains much the same, large numbers of people somehow associate it with greetings(which is false).

It is used unecessarily and unsincerely these days due to most people's ignorance and failure to understand its history and true meaning.
man1:"Everyone is saying Hiyo for no reason and out of the blue."

man2:"Yes...it is used in the movie "Anchorman" and the song "Naive melody" in a completely different way."

man1:"exactly, these kids using it these days must be trying to impress people...although they're failing miserably."
by niliem October 10, 2005