A singular noun form is a word for one person, place, or thing. Some examples are:
The noun children is the plural form of the singular noun child.
The noun family is the singular form; the plural form is families.
The noun 'fun' is a singular non-count noun, it has no plural form.
The singular form for the noun people is person.
The noun coach is the singular form. The plural form is coaches.
The form thief is the singular noun; the plural form is thieves.
The noun vest is the singular form.The noun vest's is the singular possessive form.
The noun 'dish' is the singular noun. The plural form is 'dishes'.
No, clowns is a plural noun. The singular form is clown.
No, the noun 'farm' is the singular form; the plural form is farms.
The noun quilt is the singular form. The plural noun is quilts.
noun that are plural in form but singular in meaning