In web development, the term "header" refers to the top section of a website or web page, which usually contains information about the website or content. The header is usually displayed on every page of the website and often contains the logo of the website or company as well as the main navigation.

The header can also contain information such as the title of the page, the date or the author. In some cases, the header can also contain interactive elements, such as a search field or a button for logging in or registering.

The header is an important part of web design as it conveys the first impression and influences user guidance. A well-designed header can help users to quickly find the information they need and find their way around the website.

Overall, the header is an important part of any website and should be carefully planned and designed to ensure clear navigation and a positive user experience.