[AIVC, Air infiltration and ventilation glossary, 1992]:the artificial process of treating air to adjust its temperature, humidity, cleanliness, air quality, circulation and distribution as required by occupants, a process or a product in the space(see cooling; dehumidification; heating; humidification)

[ASHRAE Standard 62.1]:the process of treating air to meet the requirements of a conditioned space by controlling its temperature, humidity, cleanliness, and distribution.

[EN 12792:2003, 11]:form of air treatment in which temperature, humidity, ventilation and air cleanliness are all controlled, if any of these features (excluding ventilation) is not controlled the system is termed as partial air conditioning.