1. One of a pair of shallow, curved signs, ( ), used to enclose an additional inserted word or comment and to distinguish it from the sentence in which it is found.
2. Either, or both, of the upright curved lines, ( ), used to mark off explanatory or qualifying remarks in writing or printing or to enclose a sum, product, or other expression considered or treated as a collective entity in a mathematical operation.
3. A word or phrase that comments on, or qualifies part of the sentence, in which it is found and is isolated from it by parentheses or dashes.
4. A piece of speech or writing that wanders off from the main topic.
5. Something that acts as a pause or a break in something.
6."In parenthesis" may refer to an additional qualifying, explanatory, or otherwise separate comment.
7. Etymology: "words, clauses, etc. inserted into a sentence", from Middle French parenthèse, from Late Latin parenthesis, "addition of a letter to a syllable in a word"; from Greek parenthesis. Literally, "a putting in beside", from parentithenai, "put in beside"; from para-, "beside" + en-, "in" + tithenai, "to put, to place".