1. either of a pair of curved marks ( ) used to enclose words or phrases that provide additional information
2. a word, phrase, or sentence inserted into a passage to provide additional information or explanation

Examples

• The author included his birth year in parentheses after his name.
• Please put your phone number in parentheses at the end of the sentence.
• The recipe calls for two cups of flour (sifted) and three eggs.
• Her comment about the weather was just a parenthesis in our serious discussion.
• The teacher explained that information in parentheses is usually optional.
• He added a brief parenthesis to clarify his earlier statement.
• The mathematical expression contained several sets of parentheses.