tail-flower vs houseplant

tail-flower and houseplant both are nouns.

Word	Noun	Adjective	Verb	Adverb
tail-flower	Yes	No	No	No
houseplant	Yes	No	No	No

As nouns, houseplant is a hypernym of tail-flower; that is, houseplant is a word with a broader meaning than tail-flower:

tail-flower: any of various tropical American plants cultivated for their showy foliage and flowers
houseplant: any of a variety of plants grown indoors for decorative purposes

tail-flower (noun)	houseplant (noun)
any of various tropical American plants cultivated for their showy foliage and flowers	any of a variety of plants grown indoors for decorative purposes