googolplex vs cardinal number

googolplex and cardinal number both are nouns.

Word	Noun	Adjective	Verb	Adverb
googolplex	Yes	No	No	No
cardinal number	Yes	No	No	No

As nouns, cardinal number is a hypernym of googolplex; that is, cardinal number is a word with a broader meaning than googolplex:

googolplex: a cardinal number represented as 1 followed by a googol of zeros (ten raised to the power of a googol)
cardinal number: the number of elements in a mathematical set; denotes a quantity but not the order

Other hypernyms of googolplex include cardinal.

googolplex (noun)	cardinal number (noun)
a cardinal number represented as 1 followed by a googol of zeros (ten raised to the power of a googol)	(grammar) A word that expresses a countable quantity.
	the number of elements in a mathematical set; denotes a quantity but not the order