mother-in-law's tongue vs Dieffenbachia

mother-in-law's tongue and Dieffenbachia both are nouns.

Word	Noun	Adjective	Verb	Adverb
mother-in-law's tongue	Yes	No	No	No
Dieffenbachia	Yes	No	No	No

mother-in-law's tongue (noun)	Dieffenbachia (noun)
stemless plant having narrow rigid leaves often cultivated as a houseplant	evergreen perennial herbs of tropical America with lush foliage and poisonous sap; often cultivated as houseplants
an evergreen plant with large showy dark green leaves; contains a poison that swells the tongue and throat hence the name