Beyond the comma and period
Advanced writers use a fuller set of punctuation to control rhythm, emphasis and relationships between ideas. The semicolon, colon and dash are powerful tools, but only when used correctly.
All three depend on understanding the independent clause: a group of words with a subject and verb that can stand alone as a sentence.
The semicolon ( ; )
Use 1: Join closely related independent clauses
A semicolon can connect two independent clauses that are closely related in meaning, without a coordinating conjunction.
The storm knocked out the power; we read by candlelight all evening.
The semicolon signals a closer connection than a period would.
Use 2: With conjunctive adverbs
When a conjunctive adverb (however, therefore, moreover, consequently, nevertheless, furthermore, otherwise, meanwhile) joins two independent clauses, use a semicolon before it and a comma after it.
The team practised for months; however, they lost the final game.
✗ The team practised for months, however, they lost. (comma splice)
Use 3: Separate complex list items
When list items already contain commas, use semicolons to separate them.
The tour visited Victoria, British Columbia; Regina, Saskatchewan; and Halifax, Nova Scotia.
Semicolon test
Each side of the semicolon (in uses 1 and 2) must be an independent clause. If you could replace it with a period, the semicolon is correct.
✗ Although it rained; we went hiking. (The first part is dependent.)
The colon ( : )
A colon introduces something: a list, explanation, example or quotation. Its key rule: what comes before the colon must be a complete sentence.
Use 1: Introduce a list
Pack three things: a flashlight, water and a map.
✗ The essentials are: a flashlight, water and a map. (The essentials are is incomplete; no colon needed.)
Use 2: Introduce an explanation or elaboration
She had one goal: to finish the marathon.
The results were clear: the new method worked.
The colon acts like an equal sign or a drumroll: what follows explains or completes what came before.
Use 3: Introduce a quotation formally
The principal’s message was simple: “Respect everyone.”
Other uses
- Time: 7:45 a.m.
- Ratios: 3:1
- Titles and subtitles: Canada: A People’s History
- Business letter salutations: Dear Hiring Committee:
Capitalization after a colon
In Canadian and American style, use lowercase after a colon unless the following is a proper noun, a quotation or (in some styles) a complete sentence. Follow your style guide consistently.
Dashes
The em dash ( — )
The em dash is the long dash. It creates emphasis or interruption.
Use 1: Set off information for emphasis
The answer — surprisingly — was hidden in the first chapter.
Use 2: Signal an abrupt break or change in thought
I was going to tell her — but then I changed my mind.
Use 3: Introduce a summary or explanation (informal alternative to a colon)
Courage, patience, kindness — these were her greatest strengths.
Use em dashes sparingly; overuse makes writing feel breathless.
In typing, an em dash can often be created by typing two hyphens (–) in some programs, or using a special character.
The en dash ( – )
The en dash is shorter. It shows ranges.
pages 45–62, 1939–1945, Monday–Friday, the Toronto–Montreal train
The hyphen ( – )
The hyphen is shortest. It joins words: well-known author, twenty-one, self-esteem, mother-in-law.
Parentheses ( )
Parentheses enclose supplementary information, which is less emphatic than information set off with dashes.
The novel (first published in 1960) remains widely taught.
Commas vs. dashes vs. parentheses
All three can set off extra information, but with different emphasis:
- Commas: neutral. My sister, a nurse, works nights.
- Dashes: emphatic. My sister — a nurse who has worked nights for twenty years — finally retired.
- Parentheses: de-emphasized. My sister (a nurse) works nights.
Choosing the right mark
| Purpose | Mark |
|---|---|
| Join two related independent clauses | semicolon |
| Join clauses with however, therefore | semicolon + comma |
| Separate list items containing commas | semicolon |
| Introduce a list or explanation after a full sentence | colon |
| Emphasize or interrupt | em dash |
| Show a range | en dash |
| Add a quiet aside | parentheses |
Worked examples
Example 1: I studied all night, therefore I passed.
Comma splice. Fix: I studied all night; therefore, I passed.
Example 2: The recipe needs: flour, sugar and eggs.
Remove the colon or complete the sentence: The recipe needs three ingredients: flour, sugar and eggs.
Example 3: Add emphasis: The final score, 98 to 97, was the closest in history.
The final score — 98 to 97 — was the closest in history.
Common mistakes
- Semicolon before a dependent clause.
- Colon after an incomplete sentence (such as:, including:, are:).
- Comma splices with conjunctive adverbs.
- Confusing hyphens, en dashes and em dashes.
- Overusing dashes or semicolons for style.
Try it yourself
- Punctuate: The museum was closed we went to the park instead.
- Punctuate: She brought everything she needed a tent a stove and a sleeping bag.
- Correct: We invited guests from Calgary, Alberta, Moncton, New Brunswick, and Yellowknife, Northwest Territories.
- Add dashes for emphasis: The secret ingredient which no one guessed was cinnamon.
Answers: 1. The museum was closed; we went to the park instead. 2. She brought everything she needed: a tent, a stove and a sleeping bag. 3. …from Calgary, Alberta; Moncton, New Brunswick; and Yellowknife, Northwest Territories. 4. The secret ingredient — which no one guessed — was cinnamon.
Study tip
When editing, highlight every semicolon and colon. For each semicolon, check that a period would work; for each colon, check that the words before it form a complete sentence.
Quick recap
- Semicolons join related independent clauses and separate complex list items.
- Use a semicolon before conjunctive adverbs like however.
- Colons introduce lists, explanations and quotations after a complete sentence.
- Em dashes emphasize or interrupt; en dashes show ranges; hyphens join words.
- Parentheses add quieter, supplementary information.