Antechamber
Part of speech: noun
Definition: A small room used as an entryway or reception area to a larger room.
Vestibule
Part of speech: noun
Definition: a passage, hall or room between the outer door and the interior of a building, such as a lobbyenclosed entrance at the end of a railway passenger carbody cavity, serving as or resembling an entrance to another bodily spaceA gateway to another dimension.