billion vs cardinal

billion and cardinal both are nouns.

Word	Noun	Adjective	Verb	Adverb
billion	Yes	Yes	No	No
cardinal	Yes	Yes	No	No

billion (noun)	cardinal (noun)
the number that is represented as a one followed by 9 zeros	crested thick-billed North American finch having bright red plumage in the male
the number that is represented as a one followed by 12 zeros; in the United Kingdom the usage followed in the United States is frequently seen	a variable color averaging a vivid red
a very large indefinite number (usually hyperbole)	(Roman Catholic Church) one of a group of more than 100 prominent bishops in the Sacred College who advise the Pope and elect new Popes
	the number of elements in a mathematical set; denotes a quantity but not the order

billion (adjective)	cardinal (adjective)
denoting a quantity consisting of one thousand million items or units in the United States	being or denoting a numerical quantity but not order
denoting a quantity consisting of one million million items or units in Great Britain	serving as an essential component