Definition of co-mother-in-law:
°the mother of one's son- or daughter-in-law; that is, the mother-in-law of one's son or daughter, or, the mother of one spouse in relation to the parents of the other spouse.
Definition of co-mother-in-law:
°the mother of one's son- or daughter-in-law; that is, the mother-in-law of one's son or daughter, or, the mother of one spouse in relation to the parents of the other spouse.