A cannery is a factory where food is put into cans so it will keep for a long time. Fish, fruit, vegetables, and soup often go through a cannery. The word is ordinary and a bit industrial; you hear it in news about jobs, towns, and food production, especially near the sea. It is not the shop where you buy canned food — that is just a supermarket. Though actually, in some coastal towns a cannery was once the main employer, so the word can carry a whole local history, not only a building.