parenthesis

Practice in written or printed language of placing certain statements between a pair of punctuation marks such as commas, dashes (-), and brackets (), to show that they are asides or interruptions in the normal flow of text.

Parenthetical commas are the subtlest device (‘He did it, so he said, in order to help us’); parenthetical dashes are the most emphatic and dramatic (‘He did it – so he said – in order to help us’), and brackets the most clinical (as this sentence demonstrates). Round brackets are used for everyday parentheses, square brackets for editorial asides and notes in another person's text and for the addition of missing material supplied by the editor. In spoken language these parenthetical services are provided by means of pauses, intonation, and expression, and often have an attitudinal quality (sarcasm, irony, humour), which can usually be inferred from the style and context of a written or printed sentence.