Comma in Punctuation

Glossary of Grammatical and Rhetorical Terms

Commas save lives
"Take care of the commas," said G.V. Carey, "and the other stops will take care of themselves, for the writer who handles this puny little stop correctly and sensibly can probably punctuate as well as need be" (Mind the Stop, 1958).

comma is a punctuation mark ( ,) used to indicate a separation of elements and ideas within a sentence.

The comma is the most common mark of punctuation--and the most commonly misused. "The most important function of the comma," says Richard Lederer, "is to indicate a natural pause. If you use commas in that way, without bothering to follow the gazillion rules we'll soon be laying on you, you will not be wrong often" (Comma Sense, 2005).

The so-called rules for using commas (some of which appear below) should be regarded as guidelines, not hard-and-fast laws. Experienced writers tend to bend these rules when they want to create particular stylistic effects.

Rules, Examples, and Observations

  • As a general rule, put a comma in front of a coordinating conjunction (and, but, for, nor, or, so, yet) that joins two independent clauses in a compound sentence.
  • "I sliced onions, and Bailey opened two or even three cans of sardines and allowed their juice of oil and fishing boats to ooze down and around the sides."(Maya Angelou, I Know Why the Caged Bird Sings, 1969)
  • "Grown-ups never understand anything for themselves, and it is tiresome for children to be always and forever explaining things to them." (Antoine de Saint-Exupery, The Little Prince, 1943)
  • If the two independent clauses are short, the comma can usually be omitted.
  • Use commas to separate words and phrases in a series of three or more.
  • "Everyone hollered, hooted, back-slapped, and jumped into the air." (Keith Nolan, Into Cambodia, 2008)
  • "Robert moved lumber, pounded nails, ran a chainsaw and helped to install windows." (Stephen Sorenson, Like Your Neighbor? 2005)
  • The comma in front of and--called the serial comma--is usually optional.  
  • Use a comma to separate adjectives that are coordinate (in other words, adjectives that are interchangeable before or after a noun).
  • "The books are trim, crisp, clean, especially in the moment when they arrive from the printer in a cardboard box." (John Updike, Self-Consciousness, 1989)
  • Cumulative adjectives are generally not separated by commas. 
  • "I wrote in a marble-floored room at the back of the little lavender house we rented on Essex Road." (John Updike, Self-Consciousness, 1989)
  • You can usually tell whether adjectives are coordinate by inserting and between them. If the sentence makes sense with and, the adjectives are coordinate and should be separated by commas.
  • To signal a pause, use a comma after an introductory word, phrase, or clause.
  • "For the first few days of his life, Wilbur was allowed to live in a box near the stove in the kitchen." (E.B. White, Charlotte's Web, 1952)
  • "Well, one of the pigs is a runt." (E.B. White, Charlotte's Web, 1952)
  • If the introductory element doesn't require a pause, the comma can usually be omitted.
  • Use commas to set off interrupting phrases and nonrestrictive elements--that is, words, phrases, or clauses that provide added (though not essential) information to a sentence.
  • "You think, I dare say, that our chief job is inventing new words."
    (George Orwell, Nineteen Eighty-Four, 1949)
  • "He sat back in his chair, slightly ashamed of himself, and laid down his pen."
    (George Orwell, Nineteen Eighty-Four, 1949)
  • "Someone was talking rapidly and continuously, a harsh gabble almost like the quacking of a duck, which pierced the general uproar of the room."
    (George Orwell, Nineteen Eighty-Four, 1949)
  • For rules on using commas with numbers and dates, see cardinal number.

Commas and Meaning

"The comma can alter the very meaning of a sentence. Consider:

The windows with the glass treatment are holding up well.

The windows, with the glass treatment, are holding up well.

In the latter sentence it's understood that the windows are holding up well because of the glass treatment; in the former, it can be understood that the windows, which were treated with a glass treatment, are holding up well in general.

The entire meaning of the sentence changes, simply due to the comma placement."
(Noah Lukeman, A Dash of Style: The Art and Mastery of Punctuation. W.W. Norton, 2006)

Origins and Uses of Commas

"The comma as we know it was invented by Aldo Manuzio, a printer working in Venice, circa 1500. It was intended to prevent confusion by separating things. In the Greek, komma means 'something cut off,' a segment. (Aldo was printing Greek classics during the High Renaissance. The comma was a Renaissance invention.) As the comma proliferated, it started generating confusion. Basically, there are two schools of thought: One plays by ear, using the comma to mark a pause, like dynamics in music; if you were reading aloud, the comma would suggest when to take a breath. The other uses punctuation to clarify the meaning of a sentence by illuminating its underlying structure. Each school believes that the other gets carried away. It can be tense and kind of silly, like the argument among theologians about how many angels can fit on the head of a pin."
(Mary Norris, "Holy Writ." The New Yorker, February 23 and March 2, 2015) 

William H. Gass on the Many Kinds of Commas

"Alas, there are so many kinds of commas: those that lie like rocks in the path of a sentence, slowing its gait and requiring the reader's heed to avoid a stumble; their gentler cousins, impairing a pell-mell flow of meaning the way pebbles slow a stream; commas that indicate a pause for thinking things over; commas enclosing phrases the way the small pockets in a purse hug hairpins or collect bits of loose change; commas that return us to our last stop, and those that some schoolmarm has insisted should be placed, like a traffic cop, between 'stop' and 'and.'"
(William H. Gass, "Enter a Sentence of Elizabeth Bishop's: Revision and Craft." Harper's, October 2011)

The Lighter Side of Commas

Jenna Maroney: We have to stop Jayden Tyler! He's evil, Tracy!
Tracy Jordan: He's evil Tracy? Oh, he's evil, comma, Tracy.
(Jane Krakowski and Tracy Morgan, "Audition Day." 30 Rock, 2009)

Sawyer: You're in my light, Sticks.


Shannon: Light sticks? What the hell is that supposed . . .
Sawyer: Light. Comma. Sticks. As in those legs of yours.
(Lost)

More On the Use of Commas

Pronunciation: KOM-ah

Etymology
From the Greek, "a piece cut off"