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Punctuation 101: When to Use the Comma, the Semicolon, the Colon, and the Dash

Caitlyn has both experience and formal education in many different areas.


Commas, Colons, and Dashes. Oh My!

There is probably nothing in English grammar more difficult and complicated than understanding when to use a semicolon (;) or the dash (-) versus a comma (,) and colon (:). These punctuation marks all serve a similar function - that being connecting separate clauses or interjecting a similar idea into a sentence, such as I'm doing here - and therefore can become confusing when writing.

Most people know about the comma and the colon, but the dash and the semi-colon are just as useful in writing- they can keep a sentence from being bogged down in commas!

The Comma

Whenever kids are first learning punctuation in school, one of the first ones learned after the period and the exclamation point is the comma.

The comma is used in a variety of ways. Most commonly seen is when there is a list of elements in a sentence ("Take George, Hanna, Greg, and Timothy to the baseball game this weekend.") but are also used when writing dates (December 17th, 1989), locations (Jackson, Mississippi; London, England), introductory phrases (Of course, there are three reasons to choose The Shining by Stephen King over The Passage by Justin Cronin.), separating quotes from the rest of the sentence ("I'm sick of having squash for every meal," he exclaimed to his mother.), and when using dependent clauses (While I was taking a shower, I heard a loud noise that could only be a tree falling in the back yard).

In a less technical way, commas are also used in writing to show the natural pauses in speech or for dramatic effect.

Commas can also alter the meaning of a sentence depending on its presence and where it is placed in a sentence. For example, the common joke of "Let's eat grandma!" and "Let's eat, grandma!" used to indicate the importance of a comma.

Summary of When to Use a Comma

  • when there is a list of 3 or more elements in a sentence
  • writing dates
  • locations
  • when using introductory phrases
  • separating quotes from the rest of the sentence
  • when using dependent clauses

A Special Comma: Exploring the Oxford Comma

Some people may have heard of what is called the Oxford Comma. What is it? The "Oxford Comma" is the comma that comes before "and" in a list of elements.

For example, in the sentence "I have to go get staples, ink, and pens," the comma before "and pens" is what is referred to as the Oxford Comma. Many people would write the sentence as "I have to go get staples, ink and pens," instead. Technically, one could write it that way and not break any grammar rules since the Oxford Comma is a stylistic choice in writing done for flow when reading, but it is often heavily debated that using the Oxford Comma is not only preferable- it is correct.

In the example sentence, not using the Oxford Comma between "ink" and "and" links "ink" and "pens" together. Such is also done here: Tommy, go to the grocery store and pick up tomatoes, cheese and crackers, milk, lettuce, and basil. What's the difference? "Cheese and crackers" are listed together because they go together. The cheese will be used with the crackers. Whereas the ink and pens are two separate things that will not be used together: ink for the printer and pens for writing.

It is not an important issue. The sentences' readability with or without the comma is not tarnished. They both flow just fine. It does arguably make for easier comprehension and it does look nicer than missing that comma. An opinion that will certainly be debated for years to come!

The Colon (in Grammar!)

In school, we are taught that the comma is used before introducing a list of elements in a sentence. For example: listing out examples, people, numbers, or ideas. (See what I did there?) But the colon can be used for more than just indicating there's going to be a list of groceries to pick up from the store or how many kids are coming to a birthday party. In fact, it has four grammatical uses!

The four main grammatical uses for the colon are indicating a list, adding emphasis or a description, separating two clauses when the second explains the first, and indicating a definition or explanation. It also has the bonus use of dramatic emphasis through fragmented clauses, a stylistic choice some people use in their writing.

As a List:

The class will be reading three books this year: To Kill A Mocking Bird, The Great Gatsby, and Fahrenheit 451.

Adding Emphasis/Description:

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She was so hungry she would eat just about anything, even the sandwich served over at Linguini's: made with disgusting, soggy bread and the thinnest deli meat slices at the most outrageous prices!

Separating Two Independent Clauses:

Daniel made two great points during his speech: First, that the neighborhood needed to raise funds to fix the streets so they were safer for the kids to play on. Second, that all dogs needed to be walked on leashes in the future.

Indicating a Definition/Explanation:

While researching for my essay, I stumbled across the word "lachrymose" and had to look it up repeatedly: suggestive of or tending to cause tears.

Bonus- Stylistic Emphasis:

Midnight: the hour of her demise was upon them

The Semicolon

The semicolon, despite it's name, is actually very similar to a comma in that it links two clauses – more commonly known as 'sentences' – that are closely related and not separated by a conjunction (i.e. 'but', 'and', etc.). Semicolons should also be used if commas have already been used in the sentence to make smaller separations in order to indicate a larger separation, such as when listing cities and states or months and days.

Example: New York, New York; Kansas City, Kansas; Atlanta, Georgia.

Example: Terri had to make dinner for her family; they would be there in an hour for the holidays.

The Dash

With the dash, there are actually three different dashes that can be used in a sentence: the en dash, the em dash, and the hyphen.

The "en dash" is used to indicate a span of time (1996 to 2019 -> 1996-2019), numbers (3 through 20 -> 3-20), and dates (October 17th to December 23rd -> October 17th-December 23rd). There shouldn't be a space between the dash and what it is indicating time between.

The "en dash" is also used to link words that conflict or connect to each other (ex. north-south railway), or when creating a compound adjective (ex. kid-friendly). Typically, a hyphen is used in these cases, but sometimes an en dash - which is thicker than a hyphen - is used. This is a stylistic choice and does not change anything about the hyphenated phrase.

The "em dash" is the longest dash and is used in a similar way to a parenthesis, comma, or colon for a variety of reasons. It can introduce an interjecting sentence, set off a word/clause for emphasis, or the expanding of an idea.

Examples of the "em dash":

As a Comma:

Kaitlyn went to the store, that one on the corner of 5th and 7th, to pick up milk and eggs.


Kaitlyn went to the store - that one on the corner of 5th and 7th - to pick up milk and eggs.

As a Colon:

Today they opened a new restaurant in town: an Italian bistro!


Today they opened a new restaurant in town- an Italian bistro!

As a Parenthesis:

He never was this excited (and also a little nervous) to go out on the stage and sing in front of the school before.


He never was this excited - and also a little nervous - to go out on the stage and sing in front of the school before.


When it comes to spacing, there are a few stylistic options. Technology does not treat the three symbols as different and will simply write them as "-" regardless of the differences between them. Writing a proper em dash ("—") is challenging since it does not appear on keyboards either. How it appears doesn't change the various ways you can use them, though, so if typing one is difficult or impossible, it's better to just focus on using it correctly.

Some people put spaces for a cleaner, less jumbled together look. Others don't put spacing at all. Some put a mix- spacing when interjecting in the middle of a sentence but only putting one space when used at the end of a sentence.


With no spacing (interjecting in a sentence): "Not so much for meI'm not that cold-heartedbut because of what others might say." (From A Walk to Remember by Nicholas Sparks)

With spacing (at the end of a sentence): Caroline wanted to know how to bake the cake and then it hit her Google would have the answer!

With spacing (interjecting in a sentence): Tiana was still staring intently at the couple walking through the restaurant.

With mixed spacing: Tobey could chase down any car in the city seriously, no matter how fast it was going and today that talent was going to be out to good use. Of course, then he had to go and do something no one could have anticipatedbreak his leg.

The key when it comes to spacing the em dash? Stay consistent! Pick a style you like and stick with it.

Finally, there is the "hyphen". This is the dash most people are familiar with and use the most often. The hyphen is used to join two separate elements together into one (such as in "long-term") There are no spaces put between the elements when writing them.

Final Thoughts

Though grammar can certainly be daunting - all the rules and exceptions piling up sky-high - taking the time to practice and understand why words are put in a certain order or why one punctuation mark is used over another can go a long way in terms of writing and communicating effectively.

Any example sentences of your own? Any questions on what to use in a sentence? Suggestions on other English Grammar topics? Feel free to write them in the comments below!


  • The Punctuation Guide

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Caitlyn Booth


OLUSEGUN from NIGERIA on February 06, 2021:

I love this. Thanks for sharing.

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