Certain parts of the prayer service – such as Kaddish and Kedusha – require the presence of a "Minyan," which is defined as ten adult Jewish males.
Occasionally, nine men are assembled in the sanctuary of the synagogue, and a tenth stands near the doorway, just outside the room, from where he listens to and participates in the service. This individual does not count toward the quorum of ten men. Although he is allowed to respond to Kaddish, Kedusha and the other prayers requiring a Minyan, he cannot be counted toward the Minyan unless he passes through the doorway and is situated in the same room as the other nine men. Only those men in the room can be counted for the Minyan, and not those standing outside the doorway.
