U.K. vs book token

U.K. and book token both are nouns.

Word	Noun	Adjective	Verb	Adverb
U.K.	Yes	No	No	No
book token	Yes	No	No	No

U.K. (noun)	book token (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 gift voucher that can be exchanged for books costing up to an amount given on the voucher