This document forms booklet five of the European Guide to Good Practice in Knowledge Management (KM), which is published as a CEN Workshop agreement. This booklet covers the core KM terminology that European private and public sector executives, particularly in small and medium size enterprises (SMEs) will need to know in order to have a proper understanding of KM. Readers can benefit from the content of this booklet alone, but we strongly recommend that they actually read this document along with the other booklets in the guide (all of which are complementary and crossreferenced), namely: Booklet 1Framework Booklet 2Culture Booklet 3SME Implementation Booklet 4Measurement