Metadata discussions are often closely linked to particular formats. However, facts about the natural world cannot depend on the medium used to transmit those facts. It follows that we are able to completely describe our metadata without reliance on any particular file format, and that we can distil metadata definitions from pre-existing data transfer frameworks regardless of the particular format used. This promising, if obvious, general conclusion does not specify what information needs to be provided in our format-free metadata definition. Following Spivak and Kent I suggest that it is sufficient that the metadata definitions can be expressed as functions mapping some domain to some range. This talk will explore some of the implications of this approach, including the independence of file format and metadata specification, specification of algorithms for interconversion between data files in differing formats, unification of disparate metadata projects, and simple steps to produce a complete metadata description.