mental process vs knowledge

mental process and knowledge both are nouns.

Word	Noun	Adjective	Verb	Adverb
mental process	Yes	No	No	No
knowledge	Yes	No	No	No

As nouns, knowledge is a hypernym of mental process; that is, knowledge is a word with a broader meaning than mental process:

mental process: (psychology) the performance of some composite cognitive activity; an operation that affects mental contents
knowledge: the psychological result of perception and learning and reasoning

Other hypernyms of mental process include cognition, noesis.

mental process (noun)	knowledge (noun)
(psychology) the performance of some composite cognitive activity; an operation that affects mental contents	the psychological result of perception and learning and reasoning