Predicate Nouns (Nominatives)
Predicate nouns, or predicate nominatives, are nouns that complement the subject and are connected to the subject through a linking verb. In the sentence, "I am a student," the subject is "I", the linking verb is "am" and the subject complement, or thing that explains that subject is "student"--"I" and "student" are the same thing. That's the function of a linking verb. Because the word "student" is a noun, meaning it's a person, place or thing, and because it follows a linking verb, it's called a predicate noun, or a noun that works in the predicate to help explain the subject.