Mountain Road
Mountain Trail, Mountain Path
noun
A mountain road is a mountain road! Or a mountain trail, or a mountain path.
やまみち
さんどう
Both the kanji in this word use the kun'yomi, which you learned when you learned the vocabulary. When it uses this reading, it sounds casual, and is common in conversation. It can also be read using the on'yomi, though, in which case it has a more formal feel to it. That's typical of on'yomi, which tends to add formality to a word!
子犬と山道を歩きました。
I walked the mountain trail with my puppy.
そこから山道になる。
From there on, it becomes a mountain path.
その先で山道に入る。
Beyond that point, the road enters the mountains.