tanka vs verse form

tanka and verse form both are nouns.

Word	Noun	Adjective	Verb	Adverb
tanka	Yes	No	No	No
verse form	Yes	No	No	No

As nouns, verse form is a hypernym of tanka; that is, verse form is a word with a broader meaning than tanka:

tanka: a form of Japanese poetry; the 1st and 3rd lines have five syllables and the 2nd, 4th, and 5th have seven syllables
verse form: a composition written in metrical feet forming rhythmical lines

Other hypernyms of tanka include poem.

tanka (noun)	verse form (noun)
a Tibetan religious painting on fabric	a composition written in metrical feet forming rhythmical lines
a form of Japanese poetry; the 1st and 3rd lines have five syllables and the 2nd, 4th, and 5th have seven syllables