Abstract
This document outlines the definition, key performance indicators (KPI), and assessment criteria for the Research Centre on Zero Emission Neighbourhoods in Smart Cities (ZEN research centre). This fifth version of the ZEN definition builds upon previous versions of the ZEN definition report and the ZEN definition guideline series (1). This report gives details on the ZEN definition framework. Further details on ZEN KPIs can be found in the ZEN definition guideline report version 4.0. Over 100 people involved in the ZEN research centre have contributed to this document.