one circle is a flat surface delimited by a series of points in the form of a curve.
one circumference is a continuous curved line.
The difference between circle and circumference is that the circle is all the area that is contained within the circle, while the circumference is the outer edge of the circle.
circle  Circumference  

definition  Flat surface bounded by a circle.  Curved line that delimits and contains a circle. 
Parts 


Length measurement  area  perimeter 
formula 
A= π. r2 
P= 2r.π 
What is a circle?
It is a surface composed of a series of outer points, called the circle, and all the points inside.
Since it is a flat surface, every circle has an area.
The formula to calculate the area is:
A= π. r2
The area of a circle is equal to Pi (3.1416) times the radius squared.
Parts of a circle
 bow: it is a portion of the circle formed by a curve that joins two points.
 string: is the distance between the two points of an arc.
 radio: is the distance from the center of the circle to any point on the circle. It is half the distance of the diameter.
 diameter: is the distance between two points that pass through the center of the circle. That is, twice the distance of the radius
 Centre: is the point at which all other equidistant points of the circle converge.
What is a circle?
A circle is a continuous, flat, closed curved line formed by a series of points that are equidistant from a common center.
Since the circle is a line and not a flat surface, it has no area, but it does have a perimeter.
The formula to calculate the perimeter is:
P= 2r.π
The perimeter is equal to the radius times 2 and this product is multiplied by Pi (3.1416).
Parts of a circle
A circle shares the elements of a circle (arc, chord, radius, diameter, and center), but it also has:
 Tangent line: is a straight line that touches the circle at a single point.
 Secant line: is a straight line that cuts the circle in two points.
See also Types of angles.