There is no definitive origin of the word dude. The Oxford Dictionary suggests it comes from a German dialect word meaning 'fool'. The Random House Historical Dictionary of American Slang cites an 1877 reference in an unpublished letter of the painter Frederick Remington: "Don't send me any more women or any more dudes," he told a correspondent who was sending him sketches. The term entered New York City slang in 1883, referring to a fastidiously sharp dresser, affecting sophistication. "Dude" was quickly applied to urbanites, especially Easterners vacationing in the West, who affected elaborate 'Wild West' dress, as paying visitors at a "dude ranch." The dude in "dude ranch" was a figure of mockery; an urban Easterner affecting the look and lifestyle of the Western cowboy, but only on a temporary basis.
In the 1960s and 1970s, the term "dude" was a popular part of African-American slang that was used by both males and females in referring to a male or males. The term was used in some black "street" novels of that era (e.g. Inner City Hoodlum p 58 and many other Donald Goines' novels). "Dude" was frequently used by black characters in 1970s TV shows, which included "Good Times" and "Sanford and Son". In many 1970s black films, the term was often used; for example, in the film "Blacula," the title character was referred to as "the big dude."