field vs peneplain

field and peneplain both are nouns.

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

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

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

Other hyponyms of field include flat, flood plain, floodplain, llano, moor, moorland, peneplane, snowfield, steppe, tundra.

field (noun)	peneplain (noun)
a particular kind of commercial enterprise	a more or less level land surface representing an advanced stage of erosion undisturbed by crustal movements
a place where planes take off and land
a branch of knowledge
the area that is visible (as through an optical instrument)
(mathematics) a set of elements such that addition and multiplication are commutative and associative and multiplication is distributive over addition and there are two elements 0 and 1
all of the horses in a particular horse race
all the competitors in a particular contest or sporting event
(computer science) a set of one or more adjacent characters comprising a unit of information
a piece of land cleared of trees and usually enclosed
somewhere (away from a studio or office or library or laboratory) where practical work is done or data is collected
a piece of land prepared for playing a game
a region in which active military operations are in progress
a region where a battle is being (or has been) fought
a geographic region (land or sea) under which something valuable is found
extensive tract of level open land
the space around a radiating body within which its electromagnetic oscillations can exert force on another similar body not in contact with it
a particular environment or walk of life

field (verb)	peneplain (verb)
select (a team or individual player) for a game
answer adequately or successfully
play as a fielder
catch or pick up (balls) in baseball or cricket