From WordNet (r) 3.0 (2006) [wn]:
highway
n 1: a major road for any form of motor transport [syn:
highway, main road]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Highway \High"way`\, n.
A road or way open to the use of the public, especially a
paved main road or thoroughfare between towns; in the latter
sense it contrasts with local street; as, on the highways
and byways.
Syn: Way; road; path; course.
[1913 Webster]