wetland vs bog

wetland and bog both are nouns.

Word	Noun	Adjective	Verb	Adverb
wetland	Yes	No	No	No
bog	Yes	No	Yes	No

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

wetland: a low area where the land is saturated with water
bog: wet spongy ground of decomposing vegetation; has poorer drainage than a swamp; soil is unfit for cultivation but can be cut and dried and used for fuel

Other hyponyms of wetland include peat bog, fen, fenland, marsh, marshland, swamp, swampland.

wetland (noun)	bog (noun)
a low area where the land is saturated with water	wet spongy ground of decomposing vegetation; has poorer drainage than a swamp; soil is unfit for cultivation but can be cut and dried and used for fuel

wetland (verb)	bog (verb)
	cause to slow down or get stuck
	get stuck while doing something