any connected part of the cicrle	arc
the point equidistant from the points on the circle	centre
a line segment whose endpoints lie on the circle	chord
a region bounded by two radi and arc lying between the radii	sector
a region,not containing the centre, bounded by a chord and an arc lying between a chord's endpoints	circular segment
the length of one circuit along the circle	circumference
a line segment wkose endpoints lie on the circle and which passes through the centre	diameter
a coplanar line that does not touch the circle	passant
a line segment joining the centre of the circle to any point on the circle	radius
an extended chord	secant
a region bounded by a diameter and an arc lying between diamater's endpoints	semicircle
a coplanar striaght line that touches the circle at a single point	tangent