noun
A shop that lends money in exchange for personal property left as collateral.
彼は時計を質屋に入れた。
He pawned his watch.
駅前に小さな質屋がある。
There is a small pawnshop in front of the station.
質 means 'pawn' or 'pledge' and is the root noun; 質屋 specifically refers to the shop where pawning takes place.
Compound of 質 (しち, 'pawn') and 屋 (や, 'shop').