部屋refers to a room or chamber. Historically, it comes from 戸(door/partition) and 屋(house), originally meaning a partitioned space within a house. It is also used to refer to a すもう stable (e.g., ここのえ-べや).
That is how Fuguro works. It brings 部屋 back for review right before you forget it, each time a little later, until it sticks for good. You hear it spoken aloud, and you meet it again in stories you can already read. The first five levels are free.