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A run-on sentence is a sentence in which two or more independent clauses (that is, complete sentences) are joined without appropriate punctuation or conjunction. It is generally considered to be a grammatical error, though it is occasionally used in literature and may be used as a rhetorical device. An example of a run-on is a comma splice, in which two independent clauses are joined with a comma without an accompanying coordinating conjunction. Some grammarians exclude comma splices from the definition of a run-on sentence, though this does not imply that such usage is acceptable.