The term for the projecting upper edge of a steep place is "precipice."
"Projecting" in this case means "sticking out." So a sharp projecting edge is a sharp edge that sticks out.
stupid people do it
The differences are subtle and depend entirely on context. They are all technically types of edges, though. Edge is the outside limit of an object, area, or surface. Rim is the upper or outer edge. Border is the edge or boundary. Brim is the projecting edge around the bottom of a hat or the upper edge of a cup, bowl, or other container. Verge is the edge, border, or extreme limit of something.
On the upper edge of each side
it is jig
aaa, rim , lip
It is called the Continental Shelf
An escarpment is an edge of a plateau usually a steep and jagged cliff.
The steep side of the edge of a continent is called a continental slope. This feature marks the transition between the continental shelf and the deep ocean floor.
Eaves, meaning the projecting overhang at the lower edge of a roof. In a sentence: The eaves of the roof will be 0.5m
A balcony is typically a platform projecting outward from a multi-story building with a railing or parapet on the edge. It is also an upper tier of seats found indoors at a theater or arena.
The upper edge of a ship's side is called the "gunwale." It is the top of the ship's side and provides structural support as well as a place for crew and equipment. The term is commonly used in the context of boats and smaller vessels as well.