en.wikipedia.org/wiki/Circular_segment

In geometry, a circular segment (symbol: ⌓) is a region of a circle which is "cut off"
from the rest ... The angle thus inscribed is θ/2 and is part of a right triangle.

www.mathopenref.com/pictorialindex.html

A pictorial index to the parts of a circle. A diagram with links to full definitions.

www.algebralab.org/lessons/lesson.aspx?file=Geometry_CircleDefinitions.xml

Introduction: A circle is all points equidistant from one point called the center of
the circle. Segments drawn near and through the circle create other geometrical ...

www.emathzone.com/tutorials/geometry/the-circle-and-parts-of-a-circle.html

An arc is a part of the circumference between two points or a continuous piece of
a circle. The shorter arc between P and Q is called the minor arc P Q . The ...

www.regentsprep.org/regents/math/geometry/gp16/circlesectors.htm

(Sectors are similar to "pizza pie slices" of a circle.) Semi-circle (half of circle =
half of area). Quarter-Circle (1/4 of circle = 1/4 of area). Any Sector (fractional part
...

www.mathsisfun.com/geometry/circle.html

circle. A circle is easy to make: Draw a curve that is "radius" away from a central
point. And so: ... a Tangent. And a part of the circumference is called an Arc.

www.geogebra.org/student/m149988?mobile=true

Use the Show/Hide buttons to discover the parts of a circle. Drag the points to
change the question. Use the Show/Hide buttons to display the different parts of a
...

www.coolmath.com/reference/circles-geometry

Definitions and formulas for the radius of a circle, the diameter of a circle, the
circumference (perimeter) of a circle, the area of a circle, the chord of a circle, arc
...

www.onlinemathlearning.com/diameter-of-circle.html

Parts of a Circle - Diameter, Chord, Radius, Arc, Tangent, Intersecting Circles,
Internal and External Tangents with examples, step by step solutions, definitions,
...

www.det.nsw.edu.au/eppcontent/glossary/app/resource/factsheet/4025.pdf

For more homework help, tips and info sheets go to www.schoolatoz.com.au.
Parts of a circle circumference. The boundary line or perimeter of a circle. centre.