Café Sometimes attached to a cake shop (Konditorei), where you can sit down and sample some of the cakes. Can be quite expensive.
Biergarten An open-air pub offering a selection of meals, usually hearty food (like soups or sausages).
Selbstbedienung Self-service.
Bistro A good place for breakfast, snacks, coffees and cakes.
Eisdiele/Eiscafé Ice-cream parlour.
Picknickzone Picnic area.
In non-formal settings like beer gardens or Gasthäuser (inns), sharing tables with strangers is common if all tables are occupied. You can simply ask Ist hier noch frei? (Is this seat free?). Don’t expect any further conversation at the table, except for Guten Appetit, and Auf Wiedersehen when one of the parties leaves.