niche vs hearth

niche and hearth both are nouns.

Word	Noun	Adjective	Verb	Adverb
niche	Yes	No	No	No
hearth	Yes	No	No	No

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

niche: an enclosure that is set back or indented
hearth: an open recess in a wall at the base of a chimney where a fire can be built

Other hyponyms of niche include alcove, bay, apse, apsis, cinerarium, columbarium, fireplace, open fireplace, mihrab.

niche (noun)	hearth (noun)
an enclosure that is set back or indented	home symbolized as a part of the fireplace
a small concavity	an open recess in a wall at the base of a chimney where a fire can be built
a position particularly well suited to the person who or organization which occupies it	an area near a fireplace (usually paved and extending out into a room)
(ecology) the status of an organism within its environment and community (affecting its survival as a species)