A noun is a person, place, or thing: apple, dog, horse.
A proper noun is specific noun, it must always be capitalized: John, Casey, Nikki, Florida.
A common noun is a class of people, places, or things: pets, houses, people, student.
A singular noun is one unit: dog, table, spoon, carpet.
A plural noun is more than one unit: dogs, tables, spoons, carpets.