Highway
High Road
noun, suffix
When streets and roads are combined together, you get something wide enough to be a highway!
But 街道 doesn't mean a modern highway that you drive on. It refers to the great high roads of the past that linked major cities and regions. In Japan, these were typically the Edo-period routes like 日光街道 (Nikkō Kaidō) and 中山道 (Nakasendō). It also works for other historically important routes, like ancient Rome's アッピア街道 (the Appian Way).
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. One thing to note though:
This word uses the かい reading for 街 (not がい). And even when 街道 is a suffix, it never gets rendaku'd! Remember this by imagining an olden-day highway full of people in kayaks (かい). You know, the horse-drawn kayaks people would use to travel long distances before the invention of cars. You've heard of those, right?
青梅街道
Ōme Highway
オックスフォード街道
the Oxford Road
本街道
main road
主要街道
major road, major highway
出世街道
the road to success
この街道をずっとまっすぐ行くと、そのうち京都に着きますよ。
If you keep following this highway straight, you will eventually reach Kyoto.
僕は街道を自転車で旅して、日本各地を回っています。
I'm traveling by bike along the old highways, visiting various places across Japan.
東海道、中山道、日光街道、甲州街道、奥州街道は、五街道と呼ばれ、江戸時代の五大陸上交通路であった。
The Tōkaidō, the Nakasendō, the Nikkō Kaidō, the Kōshū Kaidō, and the Ōshū Kaidō are called the Gokaidō — the five highways — and they were the five main routes used during the Edo period.