tree stump vs plant part

tree stump and plant part both are nouns.

Word	Noun	Adjective	Verb	Adverb
tree stump	Yes	No	No	No
plant part	Yes	No	No	No

As nouns, plant part is a hypernym of tree stump; that is, plant part is a word with a broader meaning than tree stump:

tree stump: the base part of a tree that remains standing after the tree has been felled
plant part: any part of a plant or fungus

Other hypernyms of tree stump include plant structure.

tree stump (noun)	plant part (noun)
the base part of a tree that remains standing after the tree has been felled	any part of a plant or fungus