There are different types of nouns. There are standard, proper, singular, and plural, to name a few. These are the first types of terms learned by students. Collective nouns refer to universal languages. They are also not capitalized. Proper nouns are specific, and they are capitalized.
Singular nouns can be either capital or not, and they are words that only count as one. Plural nouns can also be either capital or not, and they are words that count as more than one. In the sentence “She plays center on the all-state team for Maryland,” the word “Maryland” is considered to be a proper noun because it is a specific state and is capitalized. It would be a proper noun in any sentence.