walkway vs sidewalk

walkway and sidewalk both are nouns.

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

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

walkway: a path set aside for walking
sidewalk: walk consisting of a paved area for pedestrians; usually beside a street or roadway

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

walkway (noun)	sidewalk (noun)
a path set aside for walking	walk consisting of a paved area for pedestrians; usually beside a street or roadway