An ungrammatical sentence in which two or more independent clauses are conjoined without a conjunction WordNet 3.0 & Open English WordNet

A run-on is a sentence in which two or more independent clauses are joined without an appropriate punctuation or conjunction. Wikipedia

A grammatical construction Wikipedia Disambiguation

A sentence in which two or more independent clauses (i.e., complete sentences) are joined without appropriate punctuation or conjunction. OmegaWiki

A fused sentence, considered ungrammatical because it combines two (or more) independent clauses written as 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). Wiktionary