The semicolon (;) has two primary uses.
First, the semicolon is used in place of a period or conjunction to combine two sentences: He did the crime; he must do the time. Don’t use the semicolon to connect a subordinate clause to a sentence: Since he did the crime; he must do the time. In that case, use a comma. And while it’s fine to start a sentence with a conjunction, you needn’t use a semicolon before a conjunction: He did the crime; and he must do the time. In that case, you could use either a comma or no punctuation before the conjunction.
Second, the semicolon is used instead of a comma to separate elements in a list that have internal commas. For instance, we visited Tulsa, Oklahoma; Flint, Michigan; and Paducah, Kentucky. (Quite a trip.)
The colon (:) is used to connect the introduction and the completion of an idea. Whereas the function of the semicolon is to create greater separation than a comma would between pieces of a sentence, the colon creates greater connection than a comma. I own three cars: a Honda, a Mercedes, and a Kia.
Semicolons are commonly used where a colon is correct, and vice versa. When proofreading, make sure you’re using the right one.
Matthew, I mysteriously navigated away from this page and back to it while I was in the midst of typing a comment. Please forgive me if I have submitted the same comment twice.
I am enjoying this site, and can see already that I have many bad habits to unlearn. A question, though: in the same long-ago typing class where I learned the (news to me) obsolete two-spaces-after-a-period rule, I also learned the two-spaces-after-a-colon rule. May I safely assume from your sample sentence above that the colon rule is likewise defunct?
Yes. One space after all punctuation.
Thanks! And thank you for putting this site together.
All practicing attorneys that I have met use two spaces after a period. If you read any federal briefs on Lexus, you will invariably see two spaces after periods. Perhaps this is “obsolete” in many fields, but in law it has not been overruled.
MB…
It pains me to say this, but if only you were as well versed in your sentence structure and commas as you are with your semicolons and colons.
Sentences should not start with “and” nor should a comma come before the same conjunction.
“And while it’s fine[…]”
“[…]is correct, and vice versa […]
“It is rank superstition that [the word and] cannot properly begin a sentence”. Bryan Garner, Garner’s Modern American Usage at 44.
“No comma appears before the conjunction when the second clause has an understood subject … Sometimes, though, a comma is needed for clarity”. GMAU at 656.
Maybe, you should note that the clause before a colon should be an independent clause. As a writing instructor, I often see students formulate fragments by using a colon:
“In order to succeed in school, students need to: study hard, ask for help when necessary, and eat a healthy diet.”