autostrada vs superhighway

autostrada and superhighway both are nouns.

Word	Noun	Adjective	Verb	Adverb
autostrada	Yes	No	No	No
superhighway	Yes	No	No	No

As nouns, superhighway is a hypernym of autostrada; that is, superhighway is a word with a broader meaning than autostrada:

Other hypernyms of autostrada include expressway, freeway, motorway, pike, state highway, throughway, thruway.

autostrada (noun)	superhighway (noun)
an expressway in an Italian-speaking country	a broad highway designed for high-speed traffic
	an extensive electronic network (such as the internet) used for the rapid transfer of sound and video and graphics in digital form