Grammar 101: What the #$%! is a Semicolon?


Let’s be honest, you probably don’t know how to use a semicolon (;).  You’ve definitely seen it and have potentially thrown it into a paper to try and impress your English teacher, but chances are, you aren’t 100% sure when and how to use it. If that describes you, you’ve come to the right place. This Grammar 101 post will teach you exactly what the #$%! a semicolon is.

Semicolon Definition

Semicolons are actually really straightforward; use a semicolon when you’re joining two complete sentences. (See what we did there?) One of the most important grammar skills on an ACT or SAT is being able to identify complete sentences. This may seem obvious, but there will be lots and lots of questions in which you’ll see a punctuation mark (a semicolon, comma, period, or colon) and then have to read before and after that punctuation mark to figure out if the phrases are complete sentences or incomplete sentences. If you have two complete sentences, you can use a semicolon.  If one of the phrases is an incomplete sentence, you can’t use a semicolon. It’s that simple.


  • Correct: I am hungry; I eat dinner. (Both phrases are complete sentences, so a semicolon works).

  • Incorrect: I am hungry; and I eat dinner. (The second phrase is an incomplete sentence, so you can’t use a semicolon).

Now, you might be thinking, “Can’t I join two sentences with a period?” That’s a great question, and you definitely can. A period and a semicolon are interchangeable as far as an ACT or SAT is concerned. In fact, a secret ACT/SAT trick is that if you see a period as one answer and a semicolon as another answer, you can eliminate both of those answers since they serve identical grammatical purposes! If you see a problem like the one below, cross both answers off.

  • hungry; while

  • hungry. While

You should always, always look for ways to eliminate answers in grammar sections, and this is one of the most obvious ways to do just that. This post is just about the semicolon, but there are plenty of other tricks just like this one that we’ll be teaching you in future Grammar 101 posts.


If both phrases can stand on their own as sentences, then use a semicolon. If not, don’t use a semicolon.

Complete sentence; complete sentence.  

Easy as that!