anteroom       
noun [ C ]  formal uk/ˈæn.ti.ruːm/ /ˈæn.ti.rʊm/ us/ˈæn.t̬i.ruːm/ /ˈæn.t̬i.rʊm/ (also antechamber)
 (通往较大、较重要房间的)前厅,接待室,候见室
a small room, especially a waiting room, that leads into a larger, more important room
  The ministers waited for their meeting in the Cabinet anteroom. 部长们在内阁接待室等着开会。 
 Compare: lobby nounhallvestibule