Grammar and Mechanics

Use an apostrophe to indicate possession. For singular nouns, including those that end with s, add an apostrophe and an s.

For plural nouns, that end with s, add an apostrophe without an additional s.

Do not use an apostrophe for the possessive form of it.

Do not use an apostrophe with a possessive pronoun.

For titles, headings, and subheadings, capitalize the first word immediately following a colon.

When you use a colon in body text, lowercase the first word following the colon unless that word is a proper noun, or the text following the colon is an independent clause.

For more information on capitalization conventions, see Capitalization.

In a list of three or more items, separate each item, including the last one, with a comma. The final comma is known as an Oxford comma or a serial comma.

A notable exception is when you are creating citations for a social media post, and multiple sources corroborate a certain piece of information. For more information, see Citations.

Use a comma between conjunctions when they separate two independent clauses.

For more information on writing with conjunctions, see Conjunctions.

Note that, when you are writing lists with items that contain commas or other punctuation, you should list the items in an unordered list. For more information, see Unordered lists.

Use commas to introduce quotes.

Use a pair of commas to offset a nonessential clause in a sentence in the following cases:

In other cases, use a pair of em dashes to offset nonessential information. For more information, see Em dashes.

Use a comma after an introductory word, phrase, or clause.

Use a comma to separate the elements of a date or address.

In conversational UI messages, use ellipses to indicate pauses.

Use ellipses between square brackets to indicate ommitted text, such as in a block quote. Offset square brackets with spaces on either side. For sufficient context, provide three words from the block quote on either end of the ommission.

Use a pair of em dashes (—) to offset a nonessential clause in the following cases:

In other cases, use commas to offset nonessential information. For more information, see Commas. Do not add spaces around em dashes.

Use hyphens to form compound nouns when one word is abbreviated. In the examples below, the word electronic is abbreviated.

Note that email is an exception to this rule due to widespread usage.

Hyphenate two or more words if, taken together, they modify a noun.

Use hyphens to avoid duplicated letters and to avoid confusion with the resulting word.

Use hyphens to spell out compound numerals or fractions. Do not use numbers separated by a slash to express fractions (e.g. 1/2, 3/4).

See Numbers for additional guidance on writing numbers.

A suspended hyphen is when two or more similar compound modifiers appear next to each other in a sentence (e.g. for the phrase one-way street, one-way is a compound modifier that modifies street), and the word they modify is ommitted from all but the last compound modifier.

When using suspended hyphens, make sure there is a hyphen attached to all the adjectives. Use a space following all the hyphens except the last one.

For more than two suspended hyphens in a sentence, format the adjectives as a list. See Commas for more information.

You can use hyphens to delineate the items in an unordered list if you are writing for a platform that does not support rich text, such as social media. For more information on unordered lists, see Unordered lists.

Do not use two hyphens (--) in place of an em dash. For more information, see Em dashes.

Capitalize any part of a hyphenated word that would be capitalized if there were no hyphen(s). For more information, see Capitalization.

Always use parentheses in pairs. Use parentheses to offset nonessential information—that is, information that the reader does not need to know in order to understand the meaning of a sentence.

You can also use commas to offset nonessential information. See Commas for more information.

You can also use parentheses to include brief in-line examples in your content with e.g. preceding the examples. Do not add a comma, colon, or any additional punctuation mark after the second period in e.g.

If you need to draw attention to list items, or if your list is longer than three items, use an unordered list. For more information, see Unordered lists.

For parenthetical examples with only one item, whether you precede the example with e.g. or not will depend on the specificity of the example. For general or hypothetical examples, use e.g. For specific examples, do not use e.g.

Note that, when possible, it is best to provide more than one general or hypothetical example.

Place punctuation marks outside of the closing parenthesis unless they are used to separate a list (commas).

End every independent clause with a period. In the case of single-line captions for visual content, you may end a sentence fragment witha period. See Captions for visual content for more information.

Use periods to end the items in a list if the items can stand alone as sentences without the contextual phrase that precedes the list. For more information on lists, see Lists.

Use periods in body text, but not in titles, headings, subheadings, or UI labels. An exception is if the period is part of the UI label, in which case you should include the period in bold text along with the rest of the label. See Bold text.

Use double quotes to offset a direct quotation from a person.

Use single quotes to offset a quotation within a quotation.

Place punctuation marks inside of quotation marks, both double or single ones.

Use semicolons to connect together two closely related sentences, especially when they are not connected by a conjunction like and, or, or but. Use periods to connect together two sentences that are not closely related.

You can also use semicolons to separate items in a list when the items themselves include commas. However, in complex lists, it is best to use an unordered list. For more information, see Unordered lists.

Refrain from using slashes in place of or. It’s okay to use slashes when UI component labels use them. For more information on documenting UI interactions, see Bold text.

Capitalize any part of a phrase using a slash that would be capitalized if there were no slashes. For more information, see Capitalization.

Conjunctions coordinate words in the same clause, and they connect clauses or sentences together. In English, there are seven conjunctions:

When a conjunction connects two or more independent clauses (phrases that can stand alone as complete sentences), use a comma before it.

You can begin a sentence with a conjunction to prevent sentences from being too lengthy, or to emphasize certain content.

A preposition defines the relationship between a noun or pronoun and the other words in a sentence. Use prepositions to describe the following:

Learn about proper usage of verb tense and mood and subject-verb agreement from the guidelines below.