- Enclose material that is not essential to a sentence and that if not included would not alter its meaning: After a few minutes (some say less) the blaze was extinguished.
- Often enclose letters or figures to indicate subdivisions of a series: A movement in sonata form consists of the following elements: (1) the exposition, (2) the development, and (3) the recapitulation.
- Enclose figures following and confirming written-out numbers, especially in legal and business documents: The fee for my services will be two thousand dollars ($2,000.00).
- Enclose an abbreviation for a term following the written-out term, when used for the first time in a text: The patient is suffering from acquired immune deficiency syndrome (AIDS).
See also: Parentheses and Brackets.