grevillea vs silk oak

grevillea and silk oak both are nouns.

Word	Noun	Adjective	Verb	Adverb
grevillea	Yes	No	No	No
silk oak	Yes	No	No	No

As nouns, silk oak is a hyponym of grevillea; that is, silk oak is a word with a more specific, narrower meaning than grevillea:

grevillea: any shrub or tree of the genus Grevillea
silk oak: any of several Australian timber trees having usually fernlike foliage and mottled wood used in cabinetry and veneering

grevillea (noun)	silk oak (noun)
any shrub or tree of the genus Grevillea	any of several Australian timber trees having usually fernlike foliage and mottled wood used in cabinetry and veneering