How can we describe data when used as an art material? As the number of artists using data in their work increases, so too must our ability to describe the material in a way that is understood by both specialist and general audiences alike. Based on a review of existing vocabularies, glossaries and taxonomies of data, we propose our own concise taxonomy. To conclude, we propose the adoption of this concise taxonomy by artists, critics and curators, and suggest that ongoing refinement of the taxonomy takes place through crowdsourced knowledge sharing on the Web.