plain vs snowfield

plain and snowfield both are nouns.

Word	Noun	Adjective	Verb	Adverb
plain	Yes	Yes	Yes	Yes
snowfield	Yes	No	No	No

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

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

plain (noun)	snowfield (noun)
a basic knitting stitch made by putting the needle through the front of the stitch from the lefthand side	a permanent wide expanse of snow
extensive tract of level open land

plain (adjective)	snowfield (adjective)
not elaborate or elaborated; simple
lacking patterns especially in color
free from any effort to soften to disguise
clearly revealed to the mind or the senses or judgment
not mixed with extraneous elements
lacking embellishment or ornamentation
lacking in physical beauty or proportion

plain (verb)	snowfield (verb)
express complaints, discontent, displeasure, or unhappiness

plain (adverb)	snowfield (adverb)
unmistakably (`plain' is often used informally for `plainly')