crest vs upper side

crest and upper side both are nouns.

Word	Noun	Adjective	Verb	Adverb
crest	Yes	No	Yes	No
upper side	Yes	No	No	No

As nouns, upper side is a hypernym of crest; that is, upper side is a word with a broader meaning than crest:

Other hypernyms of crest include top, top side, upside.

crest (noun)	upper side (noun)
a showy growth of e.g. feathers or skin on the head of a bird or other animal	the highest or uppermost side of anything
(heraldry) in medieval times, an emblem used to decorate a helmet
the center of a cambered road
the top line of a hill, mountain, or wave
the top or extreme point of something (usually a mountain or hill)

crest (verb)	upper side (verb)
reach a high point
lie at the top of