- noun the head. This now old-fashioned usage dates from the 17th century or earlier and is a form of archaic words which survive as ‘napper’, ‘nape’ and ‘knob’.
- noun an aristocrat or VIP. Nob in this sense may derive from sense 1 (by way of the notion of a famous, prominent or swollen-headed personage), from the use of nob to designate the head on the jack card in cribbage or, more straightforwardly, as a shortening of ‘noble’ or ‘nobility’.
- noun the penis. In this sense the spelling knob is usually preferred.
- verb to copulate. A working-class usage which became fashionable in the 1970s and early 1980s. It derives from the use of (k)nob to mean the penis, and as such is usually, but not invariably, used by and about men.