couch vs divan bed

couch and divan bed both are nouns.

Word	Noun	Adjective	Verb	Adverb
couch	Yes	No	Yes	No
divan bed	Yes	No	No	No

As nouns, divan bed is a hyponym of couch; that is, divan bed is a word with a more specific, narrower meaning than couch:

Other hyponyms of couch include convertible, sofa bed, daybed, divan, love seat, loveseat, tete-a-tete, vis-a-vis, settee, squab.

couch (noun)	divan bed (noun)
an upholstered seat for more than one person	an armless couch; a seat by day and a bed by night
a narrow bed on which a patient lies during psychiatric or psychoanalytic treatment
a flat coat of paint or varnish used by artists as a primer

couch (verb)	divan bed (verb)
formulate in a particular style or language