A run-on sentence is a sentence consisting of two or more independent clauses (group of words expressing a complete thought) that is not joined properly with a period, semicolon or joined by a conjunction (like and, but, or) and that, instead, is connected improperly with a comma or without any type of punctuation.
Examples of run-on sentences:
The game will be called off if the storm continues, the weather is dangerous.
My mother slept in my bother's bed he slept on the couch.
