Wiktionary: freeway (plural freeways):
1) (US, Philippines, Parts of Canada and Australia) A highway with grade-separated crossings (rather than level crossings) and designed (and only permitted) for high-speed motor-traffic running in two directions on one separate carriageway each.
Synonyms: (Chiefly in Europe, Australia and New Zealand) motorway, (In Malaysia, Singapore and some parts of North America) expressway, (Chiefly in Quebec and France) autoroute, (Chiefly in Germany and Austria) autobahn, (If part of the Interstate Highway System) interstate, (Chiefly in Europe) controlled-access highway.
2) A toll-free highway.
Wiktionary: expressway (plural expressways):
1) (US, regional) A divided highway, especially one whose intersections and direct access to adjacent properties have been eliminated.
2) (Canada, parts of the US, Malaysia, Singapore, South Korea, Philippines) A road built to freeway standards.
3) (UK, New Zealand) A road built for high speed traffic, but not up to motorway standards or designated a motorway.
Wiktionary: motorway (plural motorways)
1) (UK, Ireland, New Zealand, Queensland, New South Wales) A highway with grade-separated crossings (rather than level crossings) and designed (and only permitted) for high-speed motor-traffic (in Europe motor vehicles with a higher speed limit than 40 km/h) running in two directions on one separate carriageway each.
Synonyms: (in parts of Australia, Canada and the U.S.) freeway, (in Malaysia, Singapore and parts of North America) expressway, (in parts of North America where freeway is unused) highway, (chiefly in Quebec and France) autoroute.
2) (chiefly US) A racetrack venue designated especially for the sport of auto racing.
Wiktionary: controlled-access highway (plural controlled-access highways):
1) A motorway with grade-separated crossings (rather than level crossings) and designed (and only permitted) for high-speed motor-traffic (in Europe motor vehicles with a higher speed limit than 40 km/h) running in two directions on one separate carriageway each.
Wiktionary: limited-access highway (plural limited-access highways)
1) Expressway.
Wiktionary: superhighway (plural superhighways):
1) (US) An expressway, especially one designed for high speeds.
2) (by extension) A major route that carries most of the traffic going in a given direction by a specified mode of transportation.
3) (figurative) The primary mechanism used in the movement of electronic data or information; information superhighway.