the Alps
Refers specifically to the European Alps. In Japanese it is used as a noun and place-name expression.
夏にスイス側のアルプスを旅行した。
I traveled through the Swiss side of the Alps in summer.
high mountain range; Alps-like range
Used more generally, especially as part of proper names such as 日本アルプス, to mean a range of high mountains.
日本アルプスには三千メートル級の山が多い。
The Japan Alps have many mountains around three thousand meters high.