I’m not stupid, but: how do semicolons work?

Punctuation lovers are always complaining about the decline of the semicolon. It seems to be gradually disappearing from the printed word entirely, being replaced by the comma, which serves a related but different purpose.

Sadly, the distinction between the comma and the semicolon is a really useful one for comprehending sentences correctly the first time.

The rule for when to use a semicolon is actually really straightforward; once you know it, you’ll probably never confuse it and the comma again.

Use a semicolon when you want to connect two strongly related phrases that could stand on their own as sentences.

Here’s an example I saw on the Manchester Metrolink tram the other day. When a stop is announced, an LED marquee displays something like the following:

This is an Altrincham service, the next stop will be Cornbrook.

Here a comma is used when a semicolon would be much better. Reading this sentence with a comma causes the reader to double-back and try to work out how the second part fits with the first part. A semicolon would break the sentence up properly and alert the reader to there being two separate phrases in the sentence.

This is an Altrincham service; the next stop will be Cornbrook.

The stop system gives us four “levels” of stop and, in most cases, the rules are pretty simple:

  • Comma [,]: Most of the time the comma is used to delimit non-defining clauses, like “in most cases” above. A non-defining clause is a piece of the sentence that can be removed but cannot stand on its own as a sentence. Commas are also used to separate items in a list.
  • Semicolon [;]: As above, the semicolon is used to join two phrases that could stand alone as sentences but are strongly related to one another.
  • Colon [:]: The colon does the same thing as the semicolon, except it usually ties together one phrase with an explanation of that phrase. For example, “Rich is a blogger: someone who writes pedantic articles on the web.”
  • Full stop [.]: Separates entire sentences, as I’m sure you know.

Join me in reclaiming the semicolon and making long sentences easier to read!


  1. Emily
    Sep 23, 2011

    I have an important comment for Rich Daley: excellent blog post; it cleared up a lot of punctuation confusion, examples of which are commonplace.

    • Rich
      Sep 24, 2011

      Very good!

  2. Matthew
    Sep 24, 2011

    Semicolon is for ending the line of code. Comma is for concatenating strings in Php. Simple!

  3. Geraint North
    Oct 1, 2011

    Absolutely agree, but how could you talk about semicolons without mentioning http://theoatmeal.com/comics/semicolon?

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