stepmothers
No, it is a possessive noun. Mothers is a plural noun.
The plural is toothpastes.
Much does not have a plural form.
Wizards is the plural form.
The plural form for the noun memo is memos.
The plural of step-son is step-sons.
step sisters
The plural form of the noun woman is women.The plural form of the noun mother-in-law is mothers-in-law.
The plural of the noun mother (female parent) is mothers.
The plural form of the noun mother-in-law is mothers-in-law.
The plural form for the noun mother is mothers. The plural possessive form is mothers'.Example: The mothers of several students have formed a mothers' committee.
The plural form of the noun mother is mothers.The plural possessive form is mothers'.Example: Since several fathers have joined the mothers' committee, it is now the parents' committee.
The plural form of the singular compound noun stepchild is stepchildren.
stepsisters
The plural form of the compound noun mother-in-law is mothers-in-law. The plural possessive form is mothers-in-law's. example: Both of our mothers-in-law's nationality is Irish.
Mother-of-pearl does not have a plural form; neither does its technical term, nacre.The two terms refer to the internal layer of some mollusc shells, usually described as mother-of-pearl or nacre when speaking of its use for decorative purposes.You could certainly refer to mother-of-pearl shells, or nacreous shells, as a plural form.
The plural form of the compound noun mother-in-law is mothers-in-law. The plural possessive form is mothers-in-law's. example: Both of our mothers-in-law's nationality is Irish.