Introduction to the Basic Rules of Punctuation

Conventions and Guidelines

Like many of the so-called "laws" of grammar, the rules for using punctuation would never hold up in court. These rules, in fact, are conventions that have changed over the centuries. They vary across national boundaries (American punctuation, followed here, differs from British practice) and even from one writer to the next.

Until the 18th century, punctuation was primarily related to spoken delivery (elocution), and the marks were interpreted as pauses that could be counted out.

For example, in An Essay on Elocution (1748), John Mason suggested this sequence of pauses: "A Comma stops the Voice while we may privately tell one, a Semi-colon two; a Colon three; and a Period four." This declamatory basis for punctuation gradually gave way to the syntactic approach used today.

Understanding the principles behind the common marks of punctuation should strengthen your understanding of grammar and help you to use the marks consistently in your own writing. As Paul Robinson observes in his essay "The Philosophy of Punctuation" (in Opera, Sex, and Other Vital Matters, 2002), "Punctuation has the primary responsibility of contributing to the plainness of one's meaning. It has the secondary responsibility of being as invisible as possible, of not calling attention to itself."

With these goals in mind, we'll direct you to guidelines for correctly using the most common marks of punctuation: periods, question marks, exclamation points, commas, semicolons, colons, dashes, apostrophes, and quotation marks.

End Punctuation: Periods, Question Marks, and Exclamation Points

There are only three ways to end a sentence: with a period (.), a question mark (?), or an exclamation point (!). And because most of us state far more often than we question or exclaim, the period is by far the most popular end mark of punctuation.

The American period, by the way, is more commonly known as a full stop in British English. Since around 1600, both terms have been used to describe the mark (or the long pause) at the end of a sentence.

Until the 20th century, the question mark was more commonly known as a point of interrogation--a descendant of the mark used by medieval monks to show voice inflection in church manuscripts. The exclamation point has been used since the 17th century to indicate strong emotion, such as surprise, wonder, disbelief, or pain.

Here are the present-day guidelines for using periods, question marks, and exclamation points.

More about periods, question marks, & exclamation points:


The most popular mark of punctuation, the comma (,) is also the least law-abiding. In Greek, the komma was a "piece cut off" from a line of verse--what in English today we'd call a phrase or a clause. Since the 16th century, the word comma has referred to the mark that sets off words, phrases, and clauses.

Keep in mind that these four guidelines for using commas effectively are only guidelines: there are no unbreakable rules for using commas.

Semicolons, Colons, and Dashes

These three marks of punctuation--the semicolon (;), colon (:), and dash (--)--can be effective when used sparingly.

Like the comma, the colon originally referred to a section of a poem; later its meaning was extended to a clause in a sentence and finally to a mark that set off a clause.

Both the semicolon and the dash became popular in the 17th century, and since then the dash has threatened to take over the work of other marks. Poet Emily Dickinson, for instance, relied on dashes instead of commas. Novelist James Joyce preferred dashes to quotation marks (which he called "perverted commas"). And nowadays many writers avoid semicolons (which some consider being rather stuffy and academic), using dashes in their place.

In fact, each of these marks has a fairly specialized job, and the guidelines for using semicolons, colons, and dashes aren't especially tricky.


The apostrophe (') may be the simplest and yet most frequently misused mark of punctuation in English.

It was introduced into English in the 16th century from Latin and Greek, in which it served to mark the loss of letters.

The use of the apostrophe to signify possession did not become common until the 19th century, though even then grammarians could not always agree on the mark's "correct" use. As editor, Tom McArthur notes in The Oxford Companion to the English Language" (1992), "There was never a golden age in which the rules for the use of the possessive apostrophe in English were clear-cut and known, understood, and followed by most educated people."

Instead of "rules," therefore, we offer six guidelines for using the apostrophe correctly.

Quotation Marks

Quotation marks (" "), sometimes referred to as quotes or inverted commas, are punctuation marks used in pairs to set off a quotation or a piece of dialogue. A relatively recent invention, quotation marks were not commonly used before the 19th century.

Here are five guidelines for using quotation marks effectively.