copula vs swivel

copula

noun
  • A device that connects two or more keyboards of an organ. 

  • A word, usually a verb, used to link the subject of a sentence with a predicate (usually a subject complement or an adverbial), that unites or associates the subject with the predicate. 

  • A function that represents the association between two or more variables, independent of the individual marginal distributions of the variables. 

  • The act of copulation; mating. 

swivel

noun
  • 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. 

  • 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. 

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

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

  • The act of swivelling. 

  • A rotating of the hips. 

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

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