Welcome to the Purdue OWL

Brief Overview of Punctuation

When speaking, we can pause or change the tone of our voices to indicate emphasis. When writing, we use punctuation to indicate these places of emphases. This handout should help to clarify when and how to use various marks of punctuation.

Comma

Use a comma to join two independent clauses and a coordinating conjunction (and, but, or, for, nor, so).

Use a comma after an introductory phrase, prepositional phrase, or dependent clause.

Use a comma to separate elements in a series. Although there is no set rule that requires a comma before the last item in a series, it seems to be a general academic convention to include it. The examples below demonstrate this trend.

Use a comma to separate nonessential elements from a sentence. More specifically, when a sentence includes information that is not crucial to the message or intent of the sentence, enclose it in or separate it by commas.

Use a comma between coordinate adjectives (adjectives that are equal and reversible).

Use a comma after a transitional element (however, therefore, nonetheless, also, otherwise, finally, instead, thus, of course, above all, for example, in other words, as a result, on the other hand, in conclusion, in addition)

Use a comma with quoted words.

Use a comma in a date.

Use a comma in a number.

Use a comma in a personal title.

Use a comma to separate a city name from the state.

Avoid comma splices (two independent clauses joined only by a comma). Instead, separate the clauses with a period, with a comma followed by a coordinating conjunction, or with a semicolon.

Semicolon

Use a semicolon to join two independent clauses when the second clause restates the first or when the two clauses are of equal emphasis.

Use a semicolon to join two independent clauses when the second clause begins with a conjunctive adverb (however, therefore, moreover, furthermore, thus, meanwhile, nonetheless, otherwise) or a transition (in fact, for example, that is, for instance, in addition, in other words, on the other hand, even so).

Use a semicolon to join elements of a series when individual items of the series already include commas.

For more information on semicolons, please see the "90-Second Semicolon" vidcast series on the Purdue OWL YouTube Channel.

Colon

Use a colon to join two independent clauses when you wish to emphasize the second clause.

Use a colon after an independent clause when it is followed by a list, a quotation, an appositive, or other ideas directly related to the independent clause.

Use a colon at the end of a business letter greeting.

Use a colon to separate the hour and minute(s) in a time notation.

Use a colon to separate the chapter and verse in a Biblical reference.

Parenthesis

Parentheses are used to emphasize content. They place more emphasis on the enclosed content than commas. Use parentheses to set off nonessential material, such as dates, clarifying information, or sources, from a sentence.

Dash

Dashes are used to set off or emphasize the content enclosed within dashes or the content that follows a dash. Dashes place more emphasis on this content than parentheses.

Use a dash to set off an appositive phrase that already includes commas. An appositive is a word that adds explanatory or clarifying information to the noun that precedes it.

Quotation Marks

Use quotation marks to enclose direct quotations. Note that commas and periods are placed inside the closing quotation mark, and colons and semicolons are placed outside. The placement of question and exclamation marks depends on the situation.

Use quotation marks to indicate the novel, ironic, or reserved use of a word.

Use quotation marks around the titles of short poems, song titles, short stories, magazine or newspaper articles, essays, speeches, chapter titles, short films, and episodes of television or radio shows.

Do not use quotation marks in indirect or block quotations.

Italics

Underlining and italics are often used interchangeably. Before word-processing programs were widely available, writers would underline certain words to indicate to publishers to italicize whatever was underlined. Although the general trend has been moving toward italicizing instead of underlining, you should remain consistent with your choice throughout your paper. To be safe, you could check with your teacher to find out which he/she prefers. Italicize the titles of magazines, books, newspapers, academic journals, films, television shows, long poems, plays of three or more acts, operas, musical albums, works of art, websites, and individual trains, planes, or ships.

Italicize foreign words.

Italicize a word or phrase to add emphasis.

Italicize a word when referring to that word.