barbwire vs concertina

barbwire and concertina both are nouns.

Word	Noun	Adjective	Verb	Adverb
barbwire	Yes	No	No	No
concertina	Yes	No	Yes	No

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

barbwire: strong wire with barbs at regular intervals used to prevent passage
concertina: coiled barbed wire used as an obstacle

barbwire (noun)	concertina (noun)
strong wire with barbs at regular intervals used to prevent passage	free-reed instrument played like an accordion by pushing its ends together to force air through the reeds
	coiled barbed wire used as an obstacle

barbwire (verb)	concertina (verb)
	collapse like a concertina