cardinal vs billion

cardinal and billion both are nouns.

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

cardinal (noun)	billion (noun)
crested thick-billed North American finch having bright red plumage in the male	the number that is represented as a one followed by 9 zeros
a variable color averaging a vivid red	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
(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	a very large indefinite number (usually hyperbole)
the number of elements in a mathematical set; denotes a quantity but not the order

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