(they also disagree on whether it refers to the whole penis or just the head). Some people seem to think that either 'nob' or 'knob' are exclusively correct for the slang meaning of penis Nob : wealthy or upper class person (archaic) There are many meanings, I'll show with the spelling I prefer : It appears that 'knob' is generally considered more correct now, though in old english 'nob' was more common. Is there a difference between Nob and Knob or are they just alternate spellings of the same thing ?