[AIVC, Air infiltration and ventilation glossary, 1992]:
air delivered to a space and for the purpose of ventilation, heating, cooling humidification or dehumidification.

[ASHRAE Standard 62.1]:
air delivered by mechanical or natural ventilation to a space and composed of any combination of outdoor air, recirculated air, or transfer air.

[EN 16798-3:2017, 2]:
airflow entering the treated room, or air entering the system after any treatment (SUP; colour Blue).

[EN 12792:2003, 348]:
air flow entering the treated space, or air entering the system after any treatment(coded with a colour according to the number of thermodynamic treatments)

[ISO 16814:2008,3.41]:
air introduced into an enclosure by mechanical or natural means.