A straight line from the center of a circle to the outer edge is called a radius.
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.
be worn open
a circle
brim
brim
The outer edge of a circle is called the circumference.
The out edge of a cup is called the 'Rim'.
Rim
circumference
A straight line from the center of a circle to the outer edge is called a radius.
The edge of a cereal bowl is the rim.
The edge of a cereal bowl is the rim.
It is called its bounds. In the case of 2 dimensional objects, it is part of the perimeter.
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 outer edge of an animal cell is called the cell membrane, or plasma membrane. It acts as a selectively permeable barrier, regulating the passage of substances in and out of the cell.