Dick was a once-common short form of Richard; replaced by Rick or Richie, and finally by the full name itself. Rude meaning -- make that two rude meanings -- pretty much knocks this one out of consideration.
Dick Diver, main character in F. ScottFitzgerald's "Tender is the Night"
Dick Daring, character on TV's "The Replacements"
Dick Casablanca, character on TV's "VeronicaMars"
Dick Solomon, character on TV's "3rd Rock from the Sun"
Dick Grayson, aka Robin, Batman's sidekick
Dick Ryan, character in G. A. Henty's, With Moore at Corunna, and, Under Wellington's Command
Dick Gumshoe, character in video game 'Ace Attorney'
Dick, character in "The Famous Five" by Enid Blyton
Dick's, American sporting goods chain
Dick Holland, main character in G. A. Henty's, The Tiger of Mysore