set down vs plank

set down is not a noun while plank is a noun.

Word	Noun	Adjective	Verb	Adverb
set down	No	No	Yes	No
plank	Yes	No	Yes	No

As verbs, plank is a hyponym of set down; that is, plank is a word with a more specific, narrower meaning than set down:

Other hyponyms of set down include flump, plonk, plop, plump, plump down, plunk, plunk down.

set down (noun)	plank (noun)
	an endorsed policy in the platform of a political party
	a stout length of sawn timber; made in a wide variety of sizes and used for many purposes

set down (verb)	plank (verb)
put down in writing; of texts, musical compositions, etc.	cook and serve on a plank
remove (cargo, people, etc.) from and leave	cover with planks
put or settle into a position	set (something or oneself) down with or as if with a noise
cause to sit or seat or be in a settled position or place
go ashore
reach or come to rest