Comma splice
From Teflpedia
A comma splice or comma fault involves use of a comma to join two independent clauses. For example:
"It is nearly half past five, we cannot reach town before dark."
In English, this usage is usually discouraged. It's usually better to use a full stop, semi-colon or dash instead.
The comma splice is similar to, though not quite as bad as, a run-on sentence.
