copula vs weld

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. 

weld

noun
  • The joint made by welding. 

  • A herb (Reseda luteola) related to mignonette, growing in Europe, and to some extent in America, used to make a yellow dye. 

  • The yellow coloring matter or dye extracted from this plant. 

verb
  • To join two materials (especially two metals) together by applying heat, pressure and filler, either separately or in any combination. 

  • To bind together inseparably; to unite closely or intimately. 

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