The story
So called because the sentence runs on beyond the point where it should end.
Etymology from Wiktionary, CC BY-SA 4.0.
run-on sentence
Today it means: A written sentence that inappropriately joins two (or more) independent clauses into a single sentence, often with only a comma as separator (comma splice), which should be rendered either as separate sentences or as clauses joined more appropriately (such as by a semicolon or by a comma and coordinating conjunction). Full definition →