What do landforms, topography and topography in geography refer to respectively! I'm confused. What terrain? What is terrain? What about the terrain?

1. Geomorphology is the general name of various forms of the earth's surface, also known as geomorphology. The surface morphology is varied and the causes are different, which is the result of the comprehensive action of geological processes inside and outside the crust. The internal geological process causes the surface to fluctuate, controls the corridor of land and sea distribution and the regional configuration of mountains, plateaus, basins and plains, and determines the structural framework of landforms. However, external forces (running water, wind, plain)

2. Topography refers to the ups and downs and steepness of the surface morphology, including the absolute height of the surface morphology and the relative height difference or steepness of the slope.

3. Terrain refers to the general name of the shape and landform of ground objects, especially the various ups and downs of fixed objects distributed above the surface. The landform is not exactly the same, the landform is local, but the landform must be a whole feature. For example, saddles are landforms and valleys are landforms. (1)[ land form; Physical contour; The general shape of the earth's surface; Terrain]; (2) Surface morphology, including topography, natural features and artificial features; (3) Topography is a general term for features and landforms.