Dude is a slang term used to refer to a friend or partner. The term dude generally
refers to a man; the female equivalent, "dudette" is used less often. However, "dude" has evolved to encompass both genders. Dude is a slang word, and this was true even in the 1950s, when the word was used in its more traditional sense.
Historically, the word usually has been used as a noun describing a type of man, or as an interjection. The tone and inflection of the word "dude" are used to convey the various meanings. For example, someone may be a "surfer dude." "Dude" is considered to be slang, similar to the phrase "man".
"Dude" is also used alone in a sentence as an interjection denoting a feeling of surprise, happiness, disappointment, amazement or other emotions. As an interjection, a short, clipped "dude!" might be used to convey annoyance with someone, while a long, drawn-out "duuuude" conveys amazement. The word might also be used almost anywhere in a sentence in order to convey such sentiments in conversation, as in, "Listen, dude, we have to go."
Other, older definitions include those of a well-dressed male, or one who is unfamiliar with life outside a large city. These definitions may go hand-in-hand, hence the phrased definition "an Easterner in the West" (United States).
Bugs Bunny made its first appearance in 'A Wild Hare' on 27 July 1940, many years after the publishing of the book 'Sixes and Sevens'. However it can be said the phrase was made popular by Bugs Bunny.
Jack London's The Sea Wolf 1904, page 157 "what's up" I asked Wolf Larson
Some slangs/words are used so frequently that they get added to the dictionary over the years."Google" for instance was used so much ("to google up for" means "to search for something on Google") that it got added to the Oxford English Dictionary and Webster's Dictionary as a verb.