UK vs kingdom

UK and kingdom both are nouns.

Word	Noun	Adjective	Verb	Adverb
UK	Yes	No	No	No
kingdom	Yes	No	No	No

UK (noun)	kingdom (noun)
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 basic group of natural objects
	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