"Son of Sam was the first murderer anybody ever knew who could use a semicolon."
— Jimmy Breslin, Newsday
How do I use a semicolon correctly?
Semicolons sound and look so tricky. What are they, after all? Overdressed commas? Melting colons? No wonder people get intimidated.
The truth is, semicolons are easy to use correctly. They do two jobs:
1) They join independent clauses that aren’t linked with a coordinating conjunction (a word that joins two equally important clauses, e.g. "and")
2) They separate items in a “complex” list – meaning a list that has other punctuation marks within it.
Here are examples of both rules in action.
Rule No. 1 An independent clause has a subject and a verb and can stand alone as a sentence. Why join two clauses that could stand alone? This is a stylistic thing, used because the full stop of a period would provide more pause than the author wishes to insert.
For example: Grammar is fun; everyone says so.
Independent clauses set off by a transitional expression such as however or in fact also require semi-colons. Check out this example:
This sounds complex; however, it is easy to understand once you see it in action.
Usage advice: SPOGG tends not to use semicolons with transitional expressions, though. We think this kind of “pivot” within a single sentence just makes the point of the sentence trickier to absorb. If your linked clauses aren’t supporting each other in agreement, it’s better to split them. If they do agree and build on each other, by all means, use the semicolon.
Rule No. 2
Here is an example of a complex list split with semicolons:
SPOGG loves fantasy heroes despite their scars: Harry Potter, with his thunderbolt scar; Sunny Baudelaire, who has fangs and a limited vocabulary; and Frodo Baggins, who eventually loses a finger to the extremely creepy Gollum.
The sentence would not need semicolons if the clauses set off by commas weren’t there:
SPOGG loves fantasy heroes despite their scars: Harry Potter, Sunny Baudelaire, and Frodo Baggins.
(The sentence isn't nearly as good without this information, in our humble opinion).
English Prof. Corey Marvin: http://home.cerrocoso.edu/marvin/handouts/comma4.htm
Strunk and White (they get a little more persnickety): http://www.bartleby.com/141/strunk.html