igloo

noun4

1. •
   A dome-shaped Inuit shelter, constructed of blocks cut from snow.
2. •
   A cavity, or excavation, made in the snow by a seal, over its breathing hole in the sea ice.
3. •
   A kind of airfreight cargo container.

   • Since most major airlines have interline agreements, if your cargo is in an igloo or container, it can be moved as is […] — 1978
4. •
   A reinforced bunker for the storage of nuclear weapons.

   • General James Walsh signalled Strategic Air Command that the B-47 tore apart the igloo and knocked about 3 mark sixes. — 2011