This glossary seeks to clarify key concepts in the field of monitoring and evaluation (M&E) by briefly introducing some theories, approaches, techniques, methods and methodologies for the implementation and follow-up of projects, policies and programs in the field of development. The Glossary draws on traditional references in the field, such as those drawn up by the Organization for Economic Cooperation and Development (OECD), as well as knowledge produced in the global South, and aims to offer initial support to academic researchers, project managers, consultants and analysts from different sectors.