GB vs island

GB and island both are nouns.

Word	Noun	Adjective	Verb	Adverb
GB	Yes	No	No	No
island	Yes	No	No	No

GB (noun)	island (noun)
an island comprising England and Scotland and Wales	a zone or area resembling an island
a unit of information equal to 1024 mebibytes or 2^30 (1,073,741,824) bytes	a land mass (smaller than a continent) that is surrounded by water
a unit of information equal to 1000 megabytes or 10^9 (1,000,000,000) bytes
a highly toxic chemical nerve agent that inhibits the activity of cholinesterase