The CODATA Working Group (WG) on Nanomaterials held a small workshop with members of the eNanoMapper (http://www.enanomapper.net/) team at Maastricht University in the Netherlands, on 13-14 July 2015. The purpose of the meeting was to clarify and compare approaches to the description of nanomaterials, specifically the CODATA WG’s Uniform Description System for Materials on the Nanoscale (UDS) (http://dx.doi.org/10.5281/zenodo.20688) and the eNanoMapper Ontology, as described in Journal of Biomedical Semantics (2015) (http://dx.doi.org/10.1186/s13326-015-0005-5).