Testing is "an activity that determines one or more characteristics of the object of conformity assessment according to procedures". In layman's terms, it is an activity that uses instruments and equipment to evaluate according to technical standards and specifications, and the evaluation results are test data.

Inspection refers to "the activity of checking product design, product process or installation and determining whether it meets specific requirements, or determining whether it meets general requirements based on professional judgment". In layman's terms, it relies on people's experience and knowledge, and uses test data or other evaluation information to determine whether it complies with relevant regulations.

Metrology and calibration certification is "a third-party certification related to products, processes, systems or personnel". In layman's terms, it refers to the conformity assessment activities of certification bodies with third-party nature to prove that products, services, management systems and personnel meet relevant standards and technical specifications.

Certification is "a third-party certificate that formally indicates that a conformity assessment body has the ability to carry out specific conformity assessment work". In layman's terms, it refers to the conformity assessment activities of certification bodies to prove the technical capabilities of certification bodies, inspection bodies and laboratories.

From the above definitions, it can be seen that the objects of inspection, testing and certification are products, services and corporate organizations (directly facing the market), while the objects of recognition are institutions engaged in inspection, testing and certification (indirectly facing the market)