Is a floorboard a pronoun

No, floorboard is a noun, a singular, common, concrete, compound noun; a Word for a thing.

A pronoun is a Word that takes the place of a noun in a sentence. The pronoun that takes the place of the noun floorboard in a sentence is 'it'.

• This floorboard is loose, it should be fixed.

The pronoun that takes the place of the plural noun, floorboards, is they as a subject, and them as an object in a sentence.

• Some floorboards are loose. They should be fixed before someone trips on them.