oxheart vs blackheart

oxheart and blackheart both are nouns.

Word	Noun	Adjective	Verb	Adverb
oxheart	Yes	No	No	No
blackheart	Yes	No	No	No

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

Other hyponyms of oxheart include blackheart cherry.

oxheart (noun)	blackheart (noun)
large heart-shaped sweet cherry with soft flesh	heart cherry with dark flesh and skin
any of several cultivated sweet cherries having sweet juicy heart-shaped fruits	any of various diseases in which the central tissues blacken