expressway vs throughway

expressway and throughway both are nouns.

Word	Noun	Adjective	Verb	Adverb
expressway	Yes	No	No	No
throughway	Yes	No	No	No

As nouns, expressway and throughway are synonyms defined as:

expressway and throughway: a broad highway designed for high-speed traffic

Other synonyms of expressway include freeway, motorway, pike, state highway, superhighway, thruway.

expressway (noun)	throughway (noun)
a broad highway designed for high-speed traffic	a broad highway designed for high-speed traffic