rootstock vs rhizome

rootstock and rhizome both are nouns.

Word	Noun	Adjective	Verb	Adverb
rootstock	Yes	No	No	No
rhizome	Yes	No	No	No

As nouns, rootstock and rhizome are synonyms defined as:

rootstock and rhizome: a horizontal plant stem with shoots above and roots below serving as a reproductive structure

Other synonyms of rootstock include rootstalk.

rootstock (noun)	rhizome (noun)
root or part of a root used for plant propagation; especially that part of a grafted plant that supplies the roots	a horizontal plant stem with shoots above and roots below serving as a reproductive structure
a horizontal plant stem with shoots above and roots below serving as a reproductive structure