keep up vs keep on

keep up and keep on both are verbs.

Word	Noun	Adjective	Verb	Adverb
keep up	No	No	Yes	No
keep on	No	No	Yes	No

As verbs, keep on is a hyponym of keep up; that is, keep on is a word with a more specific, narrower meaning than keep up:

keep up: lengthen or extend in duration or space
keep on: allow to remain in a place or position or maintain a property or feature

Other hyponyms of keep up include continue, keep, retain.

keep up (verb)	keep on (verb)
prevent from going to bed at night	allow to remain in a place or position or maintain a property or feature
keep informed
maintain a required pace or level
keep in safety and protect from harm, decay, loss, or destruction
lengthen or extend in duration or space