say it: soo-pur-HAHY-way
superhighway is a noun meaning "a broad highway designed for high-speed traffic". It carries 2 recorded senses.
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
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for superhighway come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.