European Commission, DG Regional Policy
http://www.evalsed.info/glossary.aspx
The glossary of evaluation-related terms of the Guide to evaluation commissioned by the European Commission, DG Regional Policy. It is downloadable by clicking here and searchable on-line.

The Evaluation Center at the Western Michigan University
http://ec.wmich.edu/Glossary/glossaryList.htm
A glossary of evaluation and evaluation-related terms; by clicking on each term you will get its definition. It contains 571 terms.

OECD
http://www.oecd.org/findDocument/0,2350,en_2649_34435_1_119678_1_1_1,00.html
This is the trilingual (EN, FR, SP) Glossary of Key Terms in Evaluation and Results Based Management, developed by the DAC Network on Development Evaluation supported by OECD. From the same page you can find Glossaries also in IT, RU, CH, JP, and PT