noun (plural parentheses) see: do
Date: circa 1550
1. an amplifying or explanatory word, phrase, or sentence inserted in a passage from which it is usually set off by punctuation, a remark or passage that departs from the theme of a discourse ; digression , interlude , interval , one or both of the curved marks ( ) used in writing and printing to enclose a parenthetical expression or to group a symbolic unit in a logical or mathematical expression, parenthetical also parenthetic adjective parenthetically adverb