Meta data are independent data which contain structured information about other data and/or ressources and their characteristics. Meta data are stored either independently of or together with the data they describe. An exact defintion of meta data is difficult since the term is being used in different contexts and distinctions can vary according to perspective.

Usually there is a distinction between discipline-specific and technical/administrative meta data.

In order to raise the effectiveness of meta data, a standardisation of descriptions is necessary. By using meta data standards, meta data from different sources can be linked and processed together.