peneplain vs champaign

peneplain and champaign both are nouns.

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

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

peneplain: 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 peneplain include field, plain.

peneplain (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