thruway vs throughway

thruway and throughway both are nouns.

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

As nouns, thruway and throughway are synonyms defined as:

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

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