* Simple Subject: The core noun or pronoun that performs the action of the verb. Example: "The cat" sat on the mat.
* Complete Subject: The simple subject plus any words that modify it. Example: "The fluffy, white cat" sat on the mat.
When people say "subject," they could mean either.
* If they're talking about grammar: They likely mean the simple subject.
* If they're talking about a topic: They mean the subject matter, which can be broader than a simple subject.
For example:
* "What's the subject of your essay?" This is asking about the topic.
* "Identify the subject in this sentence." This is asking for the grammatical subject.
To avoid confusion, it's always best to clarify what you mean!