swivel vs trunnion

swivel

noun
  • A small piece of ordnance, turning on a point or swivel; called also swivel gun. 

  • A piece, such as a ring or hook, attached to another piece by a pin, in such a manner as to permit rotation about the pin as an axis. 

  • Strength of mind or character that enables one to overcome adversity; confidence; force of will. 

  • The act of swivelling. 

  • A rotating of the hips. 

  • A small, usually ball- or barrel-shaped device used in angling to connect sections of fishing lines, consisting of two rings linked via a thrust bearing pivot joint. 

verb
  • To swing or turn, as on a pin or pivot. 

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 swivel and trunnion occurred in a corpus of books? (source: Google Ngram Viewer )