When I think of a “supermarket” I’m thinking of a medium-large sized store that sells fresh produce, dry goods, canned foods, bread, dairy, and meats. It probably has a deli section where you can buy prepared food, and it may have a bakery (for donuts and bagels and cakes). It will have an aisle or two for frozen foods, and aisle or two of home, health and beauty products (light bulbs, soap, cleaning supplies, hairspray, etc). It may have sections where you can buy wine/beer, or flowers, or magazines, or basic school/office supplies. An odd few stores may have a seating area for its delicatessen.
Most supermarkets have a small section for automotive needs, usually only brake fluid, oil, window cleaning fluid, and a few tools. They sometimes have a small counter for buying film, batteries, and renting movies.
The bathrooms and employee areas are often restricted from the public, but there is usually only one employee break area. It is festooned with required-by-law posters about employee rights, minimum wage requirements, safety regulations, and so on. It might have a microwave and refrigerator for the employees.
Many grocery stores in this area are open 24/7.
Now, we do have a few stores that are super-everything stores. I know them by brand name (Fred Meyer, Wal*Mart, K-Mart, Costco) more often than by any collective name. They’re sometimes called “big box” stores because the buildings are shaped like a big box without much in the way of decor.
These “big box” stores are catch-as-catch-can for what they sell, but most often sell things like vacuum cleaners, CDs and movies, clothing, plants, a few simple furniture items, home electronics (like video games and DVD players), shoes, childrens’ toys, dishes, and towels. Occasionally they will sell area rugs, lighting fixtures, stereo equipment, and sporting goods.
I have never personally gone into a building where cars or coffins were sold alongside all that other stuff.