Parenthesis (rhetoric)

In rhetoric, a parenthesis (plural: "parentheses"; from the Greek word παρένθεσις, which comes in turn from words meaning "alongside of" and "to place") is :An explanatory or qualifying word, clause, or sentence inserted into a passage with which it doesn't necessarily have any grammatical connection, and from which it is usually marked off by round or square brackets, dashes, or commasaccording to the Oxford English Dictionary.

Examples

;Karl, a great singer, was not a good dancer.:The phrase "a great singer", set off by commas, is both an appositive and a parenthesis.;A dog (not a cat) is an animal that barks.:The phrase "not a cat" is a parenthesis.;Please, Duncan, come here!: "Duncan" is both a noun of direct address and a parenthesis.;This page -- although it cites the OED -- is unreffed:The phrase "although it cites the OED", set off by dashes, is a parenthesis.

Punctuation

While a parenthesis need not be written enclosed by the curved brackets called "parentheses", their use principally around rhetorical parentheses has made the punctuation marks the only common use for the term in most contexts.