ken vs cognizance

ken and cognizance both are nouns.

Word	Noun	Adjective	Verb	Adverb
ken	Yes	No	No	No
cognizance	Yes	No	No	No

As nouns, ken and cognizance are synonyms defined as:

ken (noun)	cognizance (noun)
range of what one can know or understand	having knowledge of
the range of vision	range of what one can know or understand
	range or scope of what is perceived