co-parent vs matron

co-parent

noun
  • Someone who shares in the parenting of a child or children, such as 

  • A godparent. 

  • A divorced or separated parent who shares custody with the other parent. 

  • A parent in a same-sex couple. 

verb
  • To act as a co-parent; to share custody of a child or children; to share in the responsibility of parenting a child or children. 

matron

noun
  • A wife or a widow, especially, one who has borne children. 

  • A mature or elderly woman. 

  • A woman of staid or motherly manners. 

  • A housekeeper, especially, a woman who manages the domestic economy of a public institution. 

  • A senior female nurse in an establishment, especially a hospital or school. 

  • A female prison officer. 

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