comma splice
Two independent clauses joined by only a comma.
Do not join two independent clauses with a comma alone. Use a period, a semicolon, or a comma plus a coordinating conjunction: The lamp died. We lit a candle. The lamp died; we lit a candle. The lamp died, so we lit a candle. A comma splice is a mistake.
Examples
UseThe lamp died, so we lit a candle.
AvoidThe lamp died, we lit a candle.