Four words have been given, out of which three are alike in some manner and one is different. Select the odd one. 

Valley, Plateau, Glacier, Hill

The odd one out is Glacier.

Here's why:

Valley, Plateau, and Hill are all types of landforms that are typically associated with elevated or raised regions of land.

Glacier, on the other hand, is a mass of ice that forms on land and moves slowly over time, which makes it distinct from the other three in terms of its nature (it's a body of ice, not a landform formed by solid earth).

Thus, Glacier is the odd one out.