(1) the expression used when addressing either someone you know
well or your significant other. (2)
sometimes used as a word to start stories with inflection. (3) a way to express
anger at someone you don't know.
(1)
dude! how's it going? (or) i really like you,
dude!
(2)
dude, so there was this guy...
(3) DUDE! GIVE ME BACK MY PURSE!