Parentheses (USA) / Brackets (UK) [ ( ) ]

Punctuation to enclose supplementary matter that is not intended to be part of the statement. At the end of a sentence, the period follows the closing parenthesis. A complete sentence within parentheses has its own punctuation - but if it qualifies as a sentence but is dependent on the surrounding material, do not capitalize the first word or end with a period. Parentheses may indicate something important, but their use is interruptive. Use parentheses in the cases listed below.

To begin, find out about the purposes for which parentheses are used. Click on a link below to read the rules and see examples, take a guided tour by clicking the 'start' button below.

1. Numeric data, including Arabic numerals confirming a spelled-out number, and for other mathematical expressions.
2. Explanation, definitions, translations, alternatives.
3. Abbreviation of the spelled-out word or vice versa, the spelled-out form of an abbreviation.
4. Bibliographical data and text references.
5. Cross-references.
6. Comments about a text.
7. Numbers or letters indicating an item in a series are enclosed as, (1), (2), (3) and (a), (b), (c). Alternatively, one may use a right parenthesis [ ) ], e.g. We need: 1) a decision on the chapter names, 2) overall approval of the proposal, and 3) agreement on who the authors will be.