The outer edge of a cup or plate is called the rim. It serves as a boundary between the content inside the cup or plate and the external environment. The rim also provides support for holding and lifting the cup or plate.
The outer edge means the furthest most point from the center. The outer edge is usually the end of the object before the dropping off point.
The top edge of a glass or cup is called the rim.
The leading edge
Radius is from the center of a circle to the outer edge. Diameter is from the outer edge to the opposite outer edge, i.e., through the center. The diameter has twice the length of the radius.
You can take a round cup or glass and set it in the middle of the paper and then taking a pencil you can trace the outer edge of the cup. You should have a perfect round circle upon completion.
The outer edge of a circle is called the circumference.
brim
brim
It is the circle's circumference
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.
circumference