Eats, Shoots and Leaves author Lynne Truss wrote eloquently about the lack of respect that the lowly comma gets despite its obvious usefulness, but I think it’s really the semicolon that’s got people baffled. I mean, it sort of looks like a comma, but then it has that extra little dot on top, so maybe it’s more like a colon.
The truth is that the semicolon performs the same function as a period. It’s just a bit more subtle than the period. A period signals the separation of two complete thoughts. It marks the spot where one thought ends and a new one begins. A semicolon does the same thing, but it also says the two ideas are connected or related in some way. It kind of blurs the separation between the two statements.
The key point to remember is that semicolons should only be used to separate independent clauses, which is really just a fancy way of saying sentence. If either of the two clauses that you’re separating is not a sentence expressing a complete thought, then you can’t use a semi colon. The title of this article, for example, uses a semicolon incorrectly because neither of the phrases on either side of the semicolon expresses a complete thought.
Here’s an example of where you could use a semicolon:
Tommy bought socks at the store; Janie got a new hat.
Both statements could stand on their own as sentences and the two statements are obviously related. A period would also be correct here, but if you wanted to emphasize the connection, the semicolon would be the better choice.