Bunkers

noun

1. A hardened shelter, often buried partly or fully underground, designed to protect the inhabitants from falling bombs or other attacks.
2. A large container or bin for storing coal, often built outside in the yard of a house. Now rare, as different types of fuels and energy sources are being used.
3. A container for storing coal or fuel oil for a ship's engine. [Also, by extension] the quantity of fuel needed to replenish that container.
4. The coal compartment on a tank engine.
5. A sand-filled hollow on a golf course.