A group of words that does not express a complete thought is called a?

A group of words that does not express a complete thought is called a phrase.

Here's why:

* Phrase: A group of related words that does not contain a subject and a verb.

* Sentence: A group of words that expresses a complete thought and contains a subject and a verb.

For example:

* Phrase: "Running through the park" (This doesn't tell us who is running or what happened after.)

* Sentence: "The dog is running through the park." (This tells us who is running and what is happening.)