boundary vs outline

boundary and outline both are nouns.

Word	Noun	Adjective	Verb	Adverb
boundary	Yes	No	No	No
outline	Yes	No	Yes	No

As nouns, outline is a hyponym of boundary; that is, outline is a word with a more specific, narrower meaning than boundary:

boundary (noun)	outline (noun)
the greatest possible degree of something	a schematic or preliminary plan
the line or plane indicating the limit or extent of something	a sketchy summary of the main points of an argument or theory
a line determining the limits of an area	the line that appears to bound an object

boundary (verb)	outline (verb)
	describe roughly or briefly or give the main points or summary of
	trace the shape of
	draw up an outline or sketch for something