[EN 12792:2003, 21]:component used to control the air flow rate by modifying the resistance(see also damper (or valve))

[EN 12792:2003, 304]:mass or volume of air entering a supply air terminal device in unit time from an upstream duct or a plenum box. It can also be the air leaving through an opening and entering a space.

[EN 12792:2003, 370]:mass or volume of air entering a space and being the total of the primary and secondary flow rate.