Longman Dictionary of Contemporary English
square bracket
noun
EXAMPLES FROM CORPUS
▪ The square bracket shows the position of the insert.
Wiktionary
square bracket
n. Either of a pair of symbols, (unsupported: [) (unsupported: ]), used for various purposes, e.g. to enclose text inserted or replaced by an editor, to indicate various mathematical operations, and to indicate a link in MediaWiki syntax.
WordNet
square bracket
n. either of two punctuation marks ([ or ]) used to enclose textual material [syn: bracket]