It's "a pair of overalls". The word "overalls" only has a plural form and cannot be preceded by the indefinite article "a".
It's "a pair of overalls". The noun "overalls" only has a plural form and cannot be preceded by the indefinite article a/an.
Every man should own a pair of overalls.
Every man should own an overalls.
Plural nouns cannot be used with numbers; however, you can use the expressions "a pair of overalls", "two pairs of overalls", "three pairs of overalls", etc.
I have to buy a new pair of overalls.
She has four pairs of overalls in the closet.
We commonly use a possessive pronoun (my, your, her, etc.) with this piece of clothing.
Her overalls are great.
But omit the determiner to talk about overalls in a general way.
Denim overalls are usually blue.
Being a plural noun, "overalls" always take a plural form of a verb. For example, we say "overalls are", and not "is"
My overalls are dirty.
My overalls is dirty.
Follow the same practice with the following nouns: