peneplane vs champaign

peneplane and champaign both are nouns.

Word	Noun	Adjective	Verb	Adverb
peneplane	Yes	No	No	No
champaign	Yes	No	No	No

As nouns, champaign is a hypernym of peneplane; that is, champaign is a word with a broader meaning than peneplane:

peneplane: a more or less level land surface representing an advanced stage of erosion undisturbed by crustal movements
champaign: extensive tract of level open land

Other hypernyms of peneplane include field, plain.

peneplane (noun)	champaign (noun)
a more or less level land surface representing an advanced stage of erosion undisturbed by crustal movements	extensive tract of level open land