This document defines the basic properties to be measured of a powdery sample of technical nanoparticles in order to determine their size, chemical content and surface area. This document also specifies measurement methods for determining each of these properties. It is intended to facilitate communication between consumers, regulators and industry regarding the properties required. It excludes properties that affect special industrial applications of powdery nanoparticles, as well as detailed measurement protocols and properties that relate to health, safety and environmental issues.