lava vs pahoehoe

lava and pahoehoe both are nouns.

Word	Noun	Adjective	Verb	Adverb
lava	Yes	No	No	No
pahoehoe	Yes	No	No	No

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

lava: rock that in its molten form (as magma) issues from volcanoes; lava is what magma is called when it reaches the surface
pahoehoe: freely flowing lava

Other hyponyms of lava include aa, pillow lava.

lava (noun)	pahoehoe (noun)
rock that in its molten form (as magma) issues from volcanoes; lava is what magma is called when it reaches the surface	freely flowing lava