tendril vs cirrus

tendril and cirrus both are nouns.

Word	Noun	Adjective	Verb	Adverb
tendril	Yes	No	No	No
cirrus	Yes	No	No	No

As nouns, cirrus is a hyponym of tendril; that is, cirrus is a word with a more specific, narrower meaning than tendril:

tendril: slender stem-like structure by which some twining plants attach themselves to an object for support
cirrus: usually coiled

Other hyponyms of tendril include cirrhus.

tendril (noun)	cirrus (noun)
slender stem-like structure by which some twining plants attach themselves to an object for support	a slender flexible animal appendage as on barnacles or crinoids or many insects; often tactile
	a wispy white cloud (usually of fine ice crystals) at a high altitude (4 to 8 miles)
	usually coiled