co-sister-in-law vs sister

co-sister-in-law

noun
  • One's brother-in-law or sister-in-law's sister; one's sibling's spouse's sister; either of two (or more) women whose siblings are married, in relation to the other. 

  • One's spouse's sister-in-law, especially one's husband's brother's wife, one's brother's wife in relation to the spouses of his siblings; either of two (or more) women who are married to brothers, in relation to the other. 

sister

noun
  • A daughter of the same parents as another person; a female sibling. 

  • A woman, in certain religious, labour or socialist circles; also as a form of address. 

  • A female member of a religious order; especially one devoted to more active service; (informal) a nun. 

  • An entity that has a special or affectionate, non-hierarchical relationship with another. 

  • A senior or supervisory nurse, often in a hospital. 

  • A node in a data structure that shares its parent with another node. 

  • Something in the same class. 

  • A black woman. 

  • Any butterfly in the genus Adelpha, so named for the resemblance of the dark-colored wings to the black habit traditionally worn by nuns. 

  • Any woman or girl with whom a bond is felt through common membership in a community, race, profession, religion, organization, or ism. 

  • A form of address to a woman. 

verb
  • To strengthen (a supporting beam) by fastening a second beam alongside it. 

How often have the words co-sister-in-law and sister occurred in a corpus of books? (source: Google Ngram Viewer )