footwear room; shoe room
A room or area, often at the entrance of a traditional Japanese building, where outdoor footwear is removed and stored before entering the main interior.
I took off my shoes in the footwear room of the inn and changed into slippers.
下足番 is the person in charge of the footwear room, while 下足室 is the room itself.
Compound of 下足 (げそく, 'footwear', literally 'lower foot') and 室 (しつ, 'room'). The term is associated with traditional Japanese architecture where shoes are removed before entering living spaces.