topography

1. N-UNCOUNT Topography is the study and description of the physical features of an area, for example, its hills, valleys, or rivers, or the representation of these features on maps. 地形學

2. N-COUNT The topography of a particular area is its physical shape, including its hills, valleys, and rivers. 地形[usu sing, with poss]

The topography of the river's basin has changed significantly since the floods. 洪水過後，這條河的流域地形已經明顯改變了。