Static HTML refers to a website built using HTML files that comprise a whole page of a website. These websites are called "static" because their content remains fixed and does not change unless the developer manually updates the file's code (unlike CMSs that use databases and dynamic content).
Static HTML websites do not have any server-side processing or dynamically generated content. As a result, they are simpler and load faster. They may have fewer security concerns compared to dynamic websites built with content management systems (CMS) like WordPress or server-side scripting languages like PHP.