A long time ago, marks of punctuation were signals to a professional orator of how long to pause between phrases, clauses, sentences, and even paragraphs. Though this rhetorical use of punctuation was abandoned more than a century ago, some people persist in thinking that punctuation (particularly commas) mark pauses. THEY DO NOT! Today, we use commas and other marks of punctuation, not for their time value, but for other grammatical purposes.

The purpose of this section is not to provide a complete and detailed discussion of every mark of punctuation in the English language. It is, rather, a place to turn for some practical explanation for punctuation usage. Avoiding punctuation errors will greatly improve the clarity of your writing. The following types of punctuation have been included here because they are marks that typically writers find troublesome. If you have a special concern, click on the link below to move to that discussion.


The Comma

It seems to most of us that there are a billion comma rules. While the rules are many, 95% of the commas that need to be put into sentences fall can be justified by one of the following seven rules (each rule is followed by an illustrative example):

  1. Use a comma with a coordinating conjunction to join two sentences. The bright morning had dawned, and Carol was ready to meet the day.
  2. Use a comma after a introductory element (a dependent clause or a long phrase). When I left for school today, I thought I had allowed plenty of time to arrive on time. I was wrong.
  3. Use commas to separate items in a simple series. She bought a dishwasher, a clothes dryer, and a sewing machine all in the same day.
  4. Use commas to separate coordinate adjectives. The noisy, careless crowd trampled over one another to get through the gate.
  5. Use commas to set off non-essential elements. Nadine, in order not to iron anymore, invested in hand steamer.
  6. Use commas in names, dates, addresses, and numbers. I was born in Artesia, California, on May 27, 1954, a bright and sunny Thursday.
  7. In rare cases, use a comma to clarify meaning. Above, the Rockies rose hundreds of feet in the air.

If you can justify using a comma for any of the above reason, you should be safe. If not, don't use one. For the remaining comma rules, consult a good handbook.


Colons and dashes are "pointers"; they bring attention to something that comes after them. They are not, however, interchangeable in their usage.

Colons are a more formal pointer, and they have special usage in joining two independent clauses. They are often used after a complete sentence to introduce a quotation, a list, a summary, or a restatement. Here are some examples:

Weight loss demands several concentrations: diet, exercise, and will power. [list]
The new lawyer needed a secretary: he needed someone with intelligence and experience. [two independent clauses]

Dashes are formed by two hyphens without spaces. Dashes are less formal, and they have special usage in setting off abrupt interruptions to the main idea of a sentence. Here are some examples:

Let me tell you about what happened to--but you've already heard about it, haven't you? [abrupt interruption]
Her cooking is bland--no salt, pepper or seasoning of any kind. [informal list]


The semicolon is used to separate items of equal grammatical weight: most often, it is used between two independent clauses, but it is also used to separate items in a series when one or more of those items already contains a comma. Here are some examples:

Each season has its own loveliness; each bird has its own song. [two independent clauses]
Several names appeared on the ballot for senior-class president: Sam, captain of the football team; Carol, head cheerleader; Norm, president of the chess club; and Dan, just a good guy. [series with internal commas]


This much-abused mark of punctuation has two functions--to form contractions/show omissions (don't / class of '76) and to show possession (Sam's book). Most people have no trouble with the first kind of usage, but they do get confused about where to put the apostrophe when showing possession. In showing possession, we always put the apostrophe after the base word.

To show possession, start with the base word. Let's take the word state for our base word. If we want to express the idea of the rights of the state, we would add the apostrophe and an s to the base word state: the state's rights. Here's another example. Let's say the base word is Kansas. If we want to to express the idea of the rights of Kansas, we would add just the apostrophe: Kansas' rights. We omit the s because adding an apostrophe and an s would make the pronunciation awkward. This is the same strategy we use when a plural noun ends in s, like cats, for example. Our base word is cats, a plural noun. To make it possessive, we would add just the apostrophe: cats'