fog vs fogbank

fog and fogbank both are nouns.

Word	Noun	Adjective	Verb	Adverb
fog	Yes	No	Yes	No
fogbank	Yes	No	No	No

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

Other hyponyms of fog include ice fog, pogonip, mist, pea-souper, pea soup.

fog (noun)	fogbank (noun)
confusion characterized by lack of clarity	a large mass of fog on the sea (as seen from a distance)
droplets of water vapor suspended in the air near the ground
an atmosphere in which visibility is reduced because of a cloud of some substance

fog (verb)	fogbank (verb)
make less visible or unclear