Heading hierarchy is the arrangement of headings on a page into levels that form its outline. In an environment where content is processed passage by passage, it has a direct effect on how the text is split up – a heading determines where one meaningful section ends and another begins, and its wording tells what the following passage is about. The rules are simple and often broken. There is one main heading per page, naming its topic. Subheadings follow in a logical sequence of levels without skipping. Phrase the heading as a question or a precise name, not as an advertising slogan, and answer it in the first sentence right below it. Do not use headings to enlarge text that is not actually a heading – a machine treats them as structure, not as formatting.
See also: Definition Sentence at the Beginning, Question-based headings, Content chunking.
