Definition from Wiktionary, the free dictionary
co-mother (plural co-mothers)
- (obsolete) the relationship of a godmother to the other god-parents, and the legal parents, of a child.
1967, Charles Wagley, Joao José Rescála, Amazon town, page 151:
- It is considered incestuous for a co-mother and co-father to have sex relations
- in polygamy, a wife of one's father who is not one's mother; that is, co-wife of one's mother
2001, Thomas Slone, One Thousand One Papua New Guinean Nights: Tales form 1972–1985, page 321:
- the two of them went to their mother's forest hut and tried to find a way to avenge their mother's death and kill their co-mother.
- in polygamy, the relationship between one co-wife and another, in respect to their children
2003, Oyèrónkẹ́ Oyěwùmi, African women and feminism: reflecting on the politics of sisterhood, page 13:
- Notwithstanding the voluminous “co-wife” literature that Western anthropologists have used to define African marriage, “co-mother” is the preferred idiom in many African cultures for expressing the relationship amongst women married into the same family.
- in a lesbian couple, the nonbirth mother (partner of the birth mother) of a child, especially one who takes an equal role in mothering the child
2004, Robert Parkin, Linda Stone, Kinship and family: an anthropological reader, page 384:
- The dilemmas engendered by the absence of a biological tie between a child and co-mother illuminate the centrality of familial rights and obligations in American kinship.
- (relationship of a godmother): cummer, gossip, commère
- (nonbirth mother, father's other wife): stepmother
- (co-wife): sister-wife