RM (Reference Material) is material, sufficiently homogeneous and stable with respect to one or more specified properties, which has been established to be fit for its intended use in a measurement process.
CRM (Certified Reference Material) is a reference material characterized by a metrologically valid procedure for one or more specified properties, accompanied by a certificate that states the value of the specified property, its associated uncertainty, and a statement of metrological traceability.
QCM (Quality Control Material) is a material intended for internal laboratory quality control. A material or substance one or more of whose property values are sufficiently homogeneous, stable and well established to be used for maintaining or monitoring measurement processes. A QCM does not have formally assigned property values or uncertainties (ISO/CD Guide 80 - Guidance for in-house Production of Reference Materials for Metrological Quality Control (QCMs)).