A conformity assessment body is a body that performs conformity assessment. Conformity assessment: Demonstration that specified requirements relating to a product, process, system, person, or body are fulfilled. The requirements can be defined in legal decrees, standards, and manufacturer's documentation or otherwise.
All conformity assessment bodies have to fulfil the specified requirements for accreditation. These are specified in the ISO/IEC 17000 series of standards and other relevant standards for accreditation.