[AIVC, Air infiltration and ventilation glossary, 1992]:hole or gap in a building envelope which is generally purpose made, for example, a door window or vent.

[AIVC, Air infiltration and ventilation glossary, 1992]:heat added or removed during a change of state of a substance i.e. solid, to a liquid to a gas or vice versa, the temperature remaining constant.(see sensible heat transfer)

(See Equivalent Leakage Area (ELA))