walkway vs skywalk

walkway and skywalk both are nouns.

Word	Noun	Adjective	Verb	Adverb
walkway	Yes	No	No	No
skywalk	Yes	No	No	No

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

Other hyponyms of walkway include ambulatory, boardwalk, catwalk, flagging, mall, promenade, pavement, sidewalk.

walkway (noun)	skywalk (noun)
a path set aside for walking	an elevated walkway between buildings (usually enclosed)