The RK&M glossary defines important concepts and terminology for the purposes of the RK&M project. Compiled by the members of the project team, it is intended as a source of terms that are commonly used within the project in order to achieve more efficient communication and thus better understanding of RK&M issues. It should be pointed out that some terms may be used and defined differently in other areas of science and technology. The glossary is a living document: it will be improved upon and grow as it is used. This document represents the second revision of the glossary.