Header

In the field of computer networking and IT (information technology), a header is defined as a piece of data that goes in front of something else. It is usually repeated as a standard part of another process. A header may be made of numerous fields, each consisting of it’s own value. Four common uses for a header: 1. For a document - a header is a combination of text and images that can be designed to appear at the top of a page when it is displayed or printed 2. For an email - a header is a part of the message that describes the sender, the recipient, level of importance and so on 3. For a computer file - a header can be a field that comes before the content of a primary file. In this scenario it may describe the length of the content and other characteristics 4. For network transmission - a header precedes a piece of data or control signal. It contains details about a file or transmission unit such as the length and whether or not other files are physically or logically associated with it.