What does "motorway" mean?

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.

What is a synonym for "motorway"?

Common synonyms include: expressway, freeway, parkway, (motor) speedway, alley, arterial.

Motorway

//ˈməʊtəweɪ// noun

noun ·Moderate ·College level

Definitions

Noun

1
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. Ireland, New-South-Wales, New-Zealand, UK
"All the R. R.'s of America will have to be furnished with a biking way and a motor way on each side of the rails."
2
a broad highway designed for high-speed traffic wordnet
3
A racetrack venue designated especially for the sport of auto racing. US
"In December, track operators replaced the crushed rock with brick, earning the motorway the nickname, Brickyard."