A highway is any public or private road or other public way on land. It is used for major roads, but also includes other public roads and public tracks: It is not an equivalent term to controlled-access highway, or a translation for autobahn, autoroute, etc.
According to Merriam Webster, the use of the term predates 12th century. According to Etymonline, “high” is in the sense of “main”.
In North American and Australian English, major roads such as controlled-access highways or arterial roads are often state highways (Canada: provincial highways). Other roads may be designated “county highways” in the US and Ontario. These classifications refer to the level of government (state, provincial, county) that maintains the roadway.
In British English, “highway” is primarily a legal term. Everyday use normally implies roads, while the legal use covers any route or path with a public right of access, including footpaths etc.
The term has led to several related derived terms, including highway system, highway code, highway patrol and highwayman.
The term highway exists in distinction to “waterway”.
a road that is not frequently travelled
an unpopular or arcane field of study
A main, direct public road, especially a multi-lane, high speed thoroughfare connecting major population centers.
Any public road for vehicular traffic.
a road or track not following a main route; a minor road or path
“the highways and byways of Dorset”
a little-known area of knowledge
“the arcane byways of the laws of privilege”
a main road, especially one connecting major towns or cities
“the highway to success”
“a six-lane highway”
(chiefly in official use) a public road
“the Highways Department”
a pathway connecting parts of one computer system or between different systems
“an information highway”