HTML is a markup language. The word markup was used by editors who marked up manuscripts when giving instructions for revisions. A markup language as it relates to browsers is a language with specific syntax that gives instructions to a web browser about how to display a page. HTML uses a pre-defined set of elements to identify content types. Elements contain one or more "tags" that contain or express content. Tags are surrounded by angle brackets, and the "closing" tag (the one that indicates the end of the content) is prefixed by a forward slash.