kingdom vs U.K.

kingdom and U.K. both are nouns.

Word	Noun	Adjective	Verb	Adverb
kingdom	Yes	No	No	No
U.K.	Yes	No	No	No

kingdom (noun)	U.K. (noun)
a basic group of natural objects	a monarchy in northwestern Europe occupying most of the British Isles; divided into England and Scotland and Wales and Northern Ireland; `Great Britain' is often used loosely to refer to the United Kingdom
a monarchy with a king or queen as head of state
the highest taxonomic group into which organisms are grouped; one of five biological categories: Monera or Protoctista or Plantae or Fungi or Animalia
the domain ruled by a king or queen
a country with a king as head of state
a domain in which something is dominant