Data format refers to the particular encoding of information contained within a file. In terms of our metaphor, a data format corresponds to the crate in which the bottles can be stored and shipped.
XML, for example, encodes data fields and their values into a hierarchically structured file, and therefore can be called a data format standard. At this point in time, most data structures in the cultural heritage community can be expressed in an official XML instantiation, such as CDWA Lite XML.