(noun)
a structure in a convent, monastery, cathedral, court, or college that consists of a covered walk with columns, opening on one towards an open space;
e.g. They were strolling in the cloister after their afternoon meal.
(noun)
a monastery or a convent, or the way of life in such an establishment;
e.g. She has decided to pursue the cloister and become a nun.
(noun)
a state of seclusion or a secluded place;
e.g. He rarely left his cloister to socialize with them.
(verb)
to seclude or isolate oneself from the world, in or as if in an establishment such as a monastery or a convent;
e.g. She decided to cloister herself in her room until she had completed the work she needed to finish.
(verb)
to surround something with a covered walkway with columns, or to be surrounded by such a structure;
e.g. The architect decided to cloister the garden at the center of the building so that it could be viewed even in poor weather.