From the Editor’s Desk: A Guide to Commas and Semicolons

Commas and semicolons aren’t a mystery to be unraveled. They have specific uses. I’ve included a crash course with all of the rules below. If your sentence doesn’t fit one of these situations, you do not need to use a comma or semicolon.

If you’ve ever wondered when to use a comma, here you go:

1. Commas separate two independent clauses joined by a coordinating conjunction (FANBOYS).
   • Ex. Harvey was a great man, and Leslie was an amazing woman.
2. Commas separate items in a series. 
   • Ex. You need nuts, bolts, and screws.
3. Commas are used after introductory phrases of more than two words.
   • Ex. By four in the afternoon, traffic is scary on the bridges.
4. Commas separate dependent clauses at the start of the sentence from the independent clause.
   • Ex. Because her alarm clock was broken, she overslept and missed the bus.
5. Commas are used to set off transitional expressions.
   • Ex. Ferns, for example, need less light than other plants.
6. Commas also set off parenthetical elements. 
   • Ex. By the way, did you see Jim today?
7. Commas set off appositives (phrases which rename nouns or pronouns).
   • Ex. Judy, our new pitcher, was late to the playoff game.
8. One word appositives are not set off when they are essential to the meaning of the sentence.
   • Ex. The poet Shelly wrote “Ode to the West Wind.”  The poet’s wife, Mary, wrote Frankenstein.
9. Commas are used with nonrestrictive relative clauses (clauses that start with who, which, or that that are not necessary to the meaning of the sentence). 
   • Ex. Raj, who is a part-time aviator, loves to tinker with machines of all kinds.
10. Commas are not used with restrictive relative clauses (clauses that begin with who, which, or that that are necessary to the meaning of the sentence).
    • Ex. People who do their work efficiently make good students.
11. Commas are also used between the elements of an address.
    • Ex. Send payment to 300 West Road, Stanford, CT 06860.
12. Commas also separate the elements of a date. 
    • Ex. The wedding is December 12, 2004.
13. Do not use a comma with a single-word address or date preceded by a preposition.
    • Ex. He arrived from Baltimore in January and stayed awhile.
14. Commas are used after answering a question with yes or no. 
    • Ex. No, I do not like this.
15. Commas are used when addressing someone specific. 
    • Ex. Annie, where did you get your gun?
16. Commas are needed after interjections like ah, oh, etc. 
    • Ex. Ah, this water is refreshing.
17. Commas are also used to contrast. 
    • Ex. Harold, not Roy, is my favorite player.

 If you’ve ever wondered when to use a semicolon, see the rules below:

1. Use a semicolon to connect two complete sentences that contain closely related ideas.
   • Ex. The concert was brilliant; the crowd gave the band a standing ovation.
   • Ex. I said I’d do it; I didn’t say when I’d do it. 
2. Use a semicolon to separate a series of items if the items are long or if they contain commas.
   • Ex. The Millenium Falcon blasted out of Mos Eisley with Obi-Wan Kenobi, the Jedi Master; Luke Skywalker, the untried farm boy; Han Solo, the scoundrel; and Chewbacca, the hairy co-pilot on board.
3. Use a semicolon to separate two complete sentences joined with transitional phrases (on the other hand, in fact, for example).
   • Ex.  The Force only works on the weak minded; for example, the stormtroopers whom Obi-Wan tricks into thinking their droids weren’t the ones they were looking for are easily fooled.
4. Use a semicolon to separate two complete sentences joined with conjunctive adverbs such as also, anyway, finally, hence, however, instead, next, therefore, and thus.  
   • Ex. The cantina was filled with alien life forms; however, the two droids were not allowed inside.

Too confusing? Here’s the short version:

1. Use a comma for lists of more than three items.
   • a. I made a list, checked it twice, and decided I was nice.
2. Use a comma between two complete sentences joined by any of these words: for, and, nor, but, or yet, so.
   • a. I made the nice list, and I am sure Santa would agree.
   • b. Evelyn was thrilled to see presents under the tree, but her favorite gift was playing in the snow.
3. Use a comma if you have started a sentence with words that don’t contain the subject (the thing doing the action), put a comma before the subject.
   • a. Because I enjoy the winter, Christmas is my favorite holiday.
   • b. Yes, I will be traveling this holiday season.
4. If you can remove the words and not change the meaning of the sentence, put them inside commas (yes, on both sides—one before the first word and one after the last word).
   • a. I will, of course, happily join your writer’s group.
   • b. John, one of my favorite writers, publishes a new book every six months.

A Note on the Oxford Comma

The Oxford Comma matters. That is all (except it isn’t… because here I go: <start rant>).

• The Oxford Comma is the comma before the “and” in a list of three or more items. Here’s why it matters:
  • We invited the strippers, JFK, and Stalin to the party.
    • Epic party! You have three (or more?) attendees—strippers, JFK, and Stalin. 
  • We invited the strippers, JFK and Stalin.
    • Umm… JFK and Stalin are the strippers? Yes. When you don’t have a second comma, whatever comes after the first comma is an example of the first thing you listed.

Bottom line: don’t use a comma or semicolon unless you need it!