A Compound Sentence is a sentence that joins two simple sentences together with a comma, conjunction or semicolon.
Simple Sentence =
Independent Clause
Compound Sentence =
An independent clause is a clause that can stand alone. It is a group of words that contains a subject and verb and expresses a complete thought.
An independent clause is a sentence.
Ex) The teens walked to the park but it was closed.
Ex) The gentleman did not know where the sound came from, so he hid behind the tree.
Semicolon
You can also use a semicolon to create a compound sentence since the two statements are equal.
Ex) The teacher applauded the class; the kids beamed with pride.
Ex) The dog ate; the cat slept.