knob vs trunnion

knob

noun
  • A rounded ornament on the hilt of an edged weapon; a pommel. 

  • A ball-shaped part of a handle, lever, etc., designed to be grabbed by the hand. 

  • The head of the penis; the glans. 

  • A rounded protuberance, especially one arising from a flat surface; a fleshy lump or caruncle. 

  • A woman's breast. 

  • A contemptible person; dick. 

  • A prominent rounded hill. 

  • A freshman at The Citadel, The Military College of South Carolina. 

  • The clitoris. 

  • A rounded control switch that can be turned on its axis, designed to be operated by the fingers. 

  • A prominent, rounded bump along a mountain ridge. 

  • A dollop, an amount just larger than a spoonful (usually referring to butter). 

  • A chunky branch-like piece, especially of a ginger rhizome. 

  • A bulb of the garlic plant consisting of multiple cloves. 

verb
  • To have sex with. 

trunnion

noun
  • One of the short stubby bearings on either side of a cannon; a gudgeon. 

  • A similar rotational bearing comprising a rotating arc or ring sliding in the groove of a stationary arc, used in machinery to allow a workpiece to be moved relative to a fixed tool. 

  • A similar rotational bearing used in automotive suspensions. 

  • A shaft, held by a bearing, at each end or side of a rotatable object. 

How often have the words knob and trunnion occurred in a corpus of books? (source: Google Ngram Viewer )