the.com/commissary

means A store or cafeteria run by an institution — military base, prison, film set — for the people stuck inside it, where you buy supplies because there's literally nowhere else to go.

from From Latin 'commissarius,' meaning someone entrusted with a charge or duty — itself from 'committere,' to commit or entrust. The word originally meant an officer delegated to handle a task, and that sense of institutional authority carried into English for officials overseeing supplies, especially in armies. By extension, the place where that delegated officer dispensed goods became known as the commissary itself — the word drifting from the person in charge to the room he was in charge of.