Page Metadata
Page Metadata is supporting information about the page contents. "Meta" is an overused prefix and "metadata" in particular tends to seemingly get abused - within the context of content authoring and for this page "metadata" reflects information which is defined outside of the main content container (and typically subjected to more specialized processing). This becomes largely a technical rather than a semantic distinction as the "metadata" may provide what amounts to structured content and conversely the content area may include elements such as navigation which fall outside the primary content.
HTML
Page-level metadata in HTML is defined within the head element.
Markdown
In many markdown systems page-level metadata can be specified as (YAML) front-matter.