verb: in carpentry, cut away (a right-angled edge or corner) to make a symmetrical sloping edge.
noun: a symmetrical sloping surface at an edge or corner.
If that final form has an edge that is at a 45-degree angle, then it is a chamfered edge. As another known definition of chamfering is cutting grooves of varying shapes, it makes sense that a chamfered edge would be considered a “transitional edge.” But if it is an edge that isn’t perpendicular, doesn’t come to a sharp point, and isn’t at 45 degrees, then it is a beveled edge.
The beveled edge is on top and the chamfered edge is on bottom.
To break it down into much simpler terms, a bevel is an edge that is sloped and a chamfer is an edge that [...] connects two surfaces.
– Bevel and Chamfer: What’s the Difference? www.jfberns.com
The words bevel and chamfer overlap in usage; in general usage they are often interchanged, while in technical usage they may sometimes be differentiated as shown in the image –Wiki
Finally, the corners have to be chamfered or beveled to avoid featuring sharp angles. The building in the picture has specifically chamfered corners, instead of just beveled, because they form 45 degree angles.