A parenthesis is a punctuation mark used to add extra information or clarification within a sentence. It is typically represented by curved brackets, like this: ( ). The information inside a parenthesis is not essential to the main point of the sentence, allowing readers to understand the sentence even if they skip the parenthetical content. In writing, parentheses can help clarify ideas or provide additional context without interrupting the flow of the main text. They are often used to include citations, explanations, or examples, making them a useful tool for enhancing clarity in communication, especially in academic and formal writing.