A conjunction that joins words or groups of equal rank?

The conjunctions that join words or groups of equal rank are called coordinating conjunctions.

Here are some examples of coordinating conjunctions:

* FANBOYS: For, And, Nor, But, Or, Yet, So

These conjunctions connect words, phrases, or clauses that are grammatically equal in structure and function.

For example:

* Words: The dog and the cat were playing.

* Phrases: He went to the store, but he didn't buy anything.

* Clauses: She studied hard, so she passed the test.