Ah, the mysterious semicolon.  I rarely see them in student papers at all, and when I do, alas, they’re rarely used correctly.  Students tell me they avoid them because they don’t know how to use them.

So today I’m going to face the mystery head-on.

First, the basics:   You need to be able to identify independent and dependent clauses.  These are the basic building blocks of all sentences.

What is an independent clause?  It’s a group of words that constitute, and can stand alone as, a complete sentence.  An independent clause has a subject and a verb, but no internal punctuation.  For example:

I like cats.

He is extremely handsome.

The most important thing to remember about being in a relationship is that you have to be friends.

As you can see, the length of the independent clause is irrelevant.  (<– This sentence is not an independent clause.  Why?  Because it contains a comma.  As I just said, independent clauses do not contain any internal punctuation.)

OK, then what’s a dependent clause?  As you might have guessed, dependent clauses are dependent.  Because they lack either a subject or a verb, or both, they are thus known as sentence fragments, and you should generally avoid using them as stand-alone sentences.  (There are stylistic exceptions to this rule, but you have to know the rule before you can break it.  I break it quite frequently myself.  The first sentence of this blog post is a fragment, but that doesn’t mean all fragments work well as sentences.)

Here are some dependent clauses:

In the rain.

Although I wanted to.

The shirt.

Running really fast.

Each of these is missing either a subject or a verb, so none of them is a complete sentence—that is, none of them is independent.  Fragments work fine in day-to-day conversation, but in written English, they’re generally regarded as one of the Three Grievous Errors and should therefore be avoided.

OK.  As I said above, independent clauses and dependent clauses are the building blocks from which sentences are built.  If you can identify what’s dependent and what’s independent, you’ve got the basics of the whole written world at your fingertips.

So into the whole written world we go.

There are four basic types of sentences.  Yep, that’s right—only four.  Every single grammatically-correct declarative sentence you have ever seen is one of these four basic types.

Here they are:

  1. IC.                           Simple sentence: one independent clause standing alone; no internal punctuation
  2. IC; IC.                    Compound sentence: independent clauses separated by semicolons; no dependent clauses, no commas
  3. DC, IC.                   Complex sentence: any number of dependent clause(s) in any combination with ONE independent clause; uses at least one comma, but no semicolons
  4. IC; DC, IC.            Compound-complex sentence: any number and any combination of BOTH dependent and independent clauses, using BOTH comma(s) and semicolon(s)

You will note that although there are only FOUR basic sentence types, TWO of them use semicolons.  This means that if you don’t use semicolons, you’re limiting your use of language by roughly 50%.

But if you can identify dependent and independent clauses, then based on this little list, you now know everything you need to know to use semicolons correctly, and you can expand your range to 100%.

You can make any sentence in the world using a combination of ICs and DCs.  All you have to remember is a couple of very simple rules:

  1. All grammatically correct sentences must contain at least one IC.
  2. If you have two or more ICs in a sentence, you need to put semicolons in between them.

You can tell me right now whether or not the following sentences are grammatically correct:

IC, IC, DC.  Correct?  Or not?  (Not.  I’ve put two ICs together without a semicolon.  This is a comma splice, sometimes called a fused sentence, and it’s the second of the Three Grievous Errors.  This is never OK.)

DC, DC, IC, DC; DC, IC, DC; IC, DC, DC.  Correct?  Or not?  (Yes!  The sentence contains three ICs, but each is separated from the others by semicolons.  Semicolons are awesome.)

IC IC.  Correct?  No.  This is a run-on sentence, the third of the Three Grievous Errors, and like the comma splice, it should also always be avoided.  In real time, this would read something like this:

I love cats they are so funny.

IC, IC.   Correct?  No.  Two ICs can’t live in the same sentence without a semicolon.  What I’ve given you here is another comma splice.  In real life, it looks like this:

I love cats, they are so funny.

Here’s a little practice for you.  See what you can make with these models:

  1. IC.                                           (Simple)
  2. IC, DC.                                   (Complex)
  3. DC, DC, DC, IC.                   (Complex)
  4. IC; IC.                                    (Compound)
  5. IC; DC, IC.                            (Compound-complex)

Here are mine:

  1. IC.                           My cats make me laugh.
  2. IC, DC.                   Dogs are great companions, but I can’t live without a cat in the house.
  3. DC, DC, DC, IC.  Even when I’m grumpy, sick, or overworked, my cats can always cheer me up.
  4. IC; IC.                    I’ve had cats all my life; I could never name a favorite.
  5. IC; DC, IC.            Every cat has its own personality; contrary to popular opinion, most of them are not remotely aloof.

I should mention that there are other uses of the semicolon as well; for instance, they’re necessary in lists, where commas exist within the list.  One super-simple example of such usage would be a sentence like this:  “I went to Chicago, Illinois; Los Angeles, California; and Tampa, Florida.”

So now you’ve got all the basics of semicolon use.  Aren’t you dying to show off your skills?  Go ahead.  Give those models a shot.  I’d love to see some of your responses in the comments!