noun
equipment room; supply room; storage room
A room in an office, school, or facility where equipment, supplies, or materials are kept.
備品室から新しいプリンターのトナーを持ってきてください。
Please bring a new printer toner from the supply room.
この学校の備品室には、体育の用具が保管されて
In this school's equipment room, physical education equipment is stored.
物置 is a general storage shed or closet, often for household items; 備品室 is more formal and typically found in institutional settings.
Compound of 備品 (supplies, equipment) and 室 (room).