A noun is a part of speech that represents a person, place, thing, or idea. Common examples of nouns include ‘cat,’ ‘city,’ and ‘happiness.’ A subject, on the other hand, is a grammatical term used to describe who or what the sentence is about. It typically performs the action of the verb in a sentence.
For instance, in the sentence ‘The dog barks,’ ‘dog’ is both a noun and the subject of the sentence because it is the one performing the action of barking. However, not all nouns serve as subjects. In the phrase ‘The ball is on the table,’ ‘ball’ is the subject, while ‘table’ is simply another noun that adds more detail but does not perform an action.
In summary, while all subjects are nouns, not all nouns are subjects. A subject specifically dictates what the sentence discusses, whereas a noun can be any naming word, regardless of its function within the sentence.