A compound sentence refers to a sentence that is made of two or more independent clauses connected together by a coordinating conjunction. The coordinating conjunctions can be easily remembered if you think of the word FANBOYS.
For; And; Nor; But; Or; Yet; So
Examples of compound sentences :
Joe waited for the train, but the train was late.
I went out for a walk, and I took my umbrella with me
Bonnie couldn’t find her dress, so she didn’t go to the party.
He didn’t study, yet he was determined to pass the exam.