112 Colons (English)

Home >> Grammar Style Guide >> Colons

Understanding Colons

A colon is a punctuation mark used to introduce one item or items that follows the colon to an item or items that precedes the colon. a colon is only used in the middle of a sentence or at the end of an independent or dependent clause, providing that something follows the colon after the independent or dependemt clause.

Colons Introducing Clauses

A colon can separate an independent clause from a dependent clause, such as when introducing a list or group of items.
In rare cases, a colon can separate two independent clauses, such as when one sentence introduces another sentence.
A colon can introduce a dependent clause or list of items from an independent or dependent clause that precedes it.
A colon can introduce a single object or group of objects in a sentence or sentence fragment. For example, Name: Papoose

Colons in List Items

A colon can be used to introduce inline list items or external list items. When introducing a list, an introductory sentence, phrase, or word must precede the colon, and at least one item must follow the colon.

Colons in Inline List Items

A colon can be used to introduce an inline list of items. Inline lists must be separated by either commas or semicolons when used as hard commas.
For example, this is a list of letters: a, b, and c.
This example is referred to as an inline list of items because the list is set within the sentence as opposed to externally.
Inline lists must have a minimum of three items listed in order to be separated by commas or semicolons.
In some instances, such as in mathematics, list items can be set off in quotes or parentheses in lieu of using a semicolons as hard commas.
For example, the list: a, b; c, d; and e, f can be written as ("a, b"), (c, d), and "e , f"

Colons in External List Items

A colon can be used to separate external list items from the sentence, phrase, or word that introduces them. When introducing an external list of items, each item can be set off with some sort of symbol, such as a bullet point. Best practices are to keep using the same symbol at equivalent indents of the list and any sublists within the list.
External lists are useful for when the list being introduced is extensive, has more than one sublist, or can be confusing or ambiguous if written inline.
When writing items in an external list, best practices are to end each list item with a comma or semicolon, use a coordinating conjunction in the penultimate list item, and end the list with a period; however, one of the benefits of external lists is that the comma or semicolon can be omitted on each line of the list without reducing the value or readability of the sentence.

Colons For Addressing People in Memos

Colons can be used instead commas when addressing an entity in a letter or memo. Common examples are office memos addressed to staff members as shown in the following example:
All staff:
Colons can be used to set off a selected option from a category; for example, Attention: All Staff

Using Double Colons

Two colons next to each other between two terms signals that the object to the right of the double colons is a subcategory of the item to the left of them.
For example:
Grammar :: Punctuation :: Colons