boundary vs perimeter

boundary and perimeter both are nouns.

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

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

boundary (noun)	perimeter (noun)
the greatest possible degree of something	the size of something as given by the distance around it
the line or plane indicating the limit or extent of something	the boundary line or the area immediately inside the boundary
a line determining the limits of an area	a line enclosing a plane areas