|em dash (—)|
|Definition - The type of dash that is — for the most part — used to indicate sudden breaks in thought.|
1. Use it for sudden breaks in thought that cause abrupt sentence structure changes.
The truth of the matter — and it is a truth that is really true — is that life IS a bowl of cherries.
2. Use it to show an open range.
Jon Smith, 1944—
3. Use it to give emphasis or explanation.
I drank 6 gallons of milk — the store's entire stock.
4. Use it to separate a name's subordinate, modifying element from its main element.
University of Quebec—Montreal
5. Use two em dashes to indicate missing letters.
Don't walk on Hast—— street.
6. Use three em dashes with a space on either side to show the omission of a whole word.
Row, row, ——— your boat.
7. Use it before a final clause that summarizes a previous series.
Love of country, love of family, love of self — these are a few of my favorite things.
8. Never use it immediately after a comma, colon, or semicolon.
If a man were to, — but why bother. (bad)
9. You can use it to introduce a list of items.
The driver said that three things were not allowed on the bus - food, water, and gum.
10. Use it to precede a credit line.
Every man's work shall be made manifest. — I Corinthians 3:13.
11. Instead of a colon, use it with a preceding question mark.
What do you mean by this? — "Anything goes."
Etymology - The symbol was called the em dash because it is the same width as the capital M.
Note: The em is the length in points by which font sizes are specified. For example, with 9-point type, the em is 9 points wide, while the 24-point type em is 24 points wide.