Other forms: isolations
Isolation means completely alone, like the stranded skiers who were in total isolation after an avalanche stranded them at the top of a mountain.
People who live in isolation are completely cut off from the rest of the world, like the hermit who lives in a lonely mountain cabin because no one understands his desire to collect thimbles. A really contagious illness can land patients in isolation at their local hospital, kept separate from the rest of the hospital so they don't share their disease with the other patients. A country can exist in isolation, left alone because other nations don't agree with its policies.