The singular form of the plural noun 'women' is woman.
The singular form of alumni is "alumnus" for male individuals, and "alumna" for female individuals.
Plural.
I'm not sure it's the only one, but "princes" becomes "princess" when an S is added.
il (sigular) ils (plural)
The belief's premise is well founded.
Cousine (sigular) or Cousinen (plural)
vocabulary can only be used in sigular form
Flagella is already the plural of flagellum.
The word women is a noun, the plural form of the noun woman, a word for a person.
The abstract noun form of the concrete noun 'women' is womanhood.
The noun 'women' is the irregular plural form. The singular noun is woman.
The noun 'women' is the irregular plural form. The singular noun is woman.