A group of words that has a subject and predicate but does not contain the complete sentence?

That's a great question! What you're describing is called a clause.

Here's a breakdown:

* Sentence: A complete thought that contains a subject (who or what the sentence is about) and a predicate (what the subject does or is). It must stand alone and make sense.

* Clause: A group of words containing a subject and a predicate, but it may not be a complete sentence on its own.

There are two main types of clauses:

* Independent Clause: Can stand alone as a complete sentence. Example: "The cat sat on the mat."

* Dependent Clause: Cannot stand alone as a complete sentence; it relies on an independent clause for its meaning. Example: "Because the cat was tired."

Let me know if you want to explore different types of clauses or have any other questions!