An HTML element, with tag name of "META", expressing metadata about a given HTML document. HTML standards do not require that documents have META elements but if META elements occur, they must be inside the document's HEAD element.
The META element can be used to identify properties of a document (e.g., author, expiration date, a list of key words, etc.) and assign values to those properties, typically by specifying a NAME attribute (to name the property) and a CONTENT attribute (to assign a value for that property). The HTML 4 specification doesn't standardise particular NAME properties or CONTENT values; but it is conventional to use a "Description" property to convey a short summary of the document, and a "Keywords" property to provide a list of keywords relevant to the document, as in:
Other properties may be application-specific. For example, the Robots Exclusion. standard uses the "robots" property for asserting that the given document should not be indexed by robots, nor should links in it be followed: