A room or place for the reception of useless or unused things; a room occupied by lumber.(noun)
The Century Dictionary (Public Domain)
Use "lumber-room" in a sentence
"Not until after a long search did we find the oar in a disused attic lumber-room of odds and ends."
""That which my son himself indicated -- that of the cupboard of the lumber-room.""
"There was one singular exception, however, for he had a single room, a lumber-room up among the attics, which was invariably locked, and which he would never permit either me or anyone else to enter."