marumi vs kumquat tree

marumi and kumquat tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
marumi	Yes	No	No	No
kumquat tree	Yes	No	No	No

As nouns, kumquat tree is a hypernym of marumi; that is, kumquat tree is a word with a broader meaning than marumi:

marumi: shrub bearing round-fruited kumquats
kumquat tree: any of several trees or shrubs of the genus Fortunella bearing small orange-colored edible fruits with thick sweet-flavored skin and sour pulp

Other hypernyms of marumi include cumquat, kumquat.

marumi (noun)	kumquat tree (noun)
shrub bearing round-fruited kumquats	any of several trees or shrubs of the genus Fortunella bearing small orange-colored edible fruits with thick sweet-flavored skin and sour pulp