A radius is a segment created between the center of a circle and a point on the circle.
From the given options, the radius is UV.
A chord is a segment created between two points on the circle.
From the given options, the chord is XS.
A diameter is a chord that passes through the center of the circle.
From the given options, the diameter is ZX.
A secant is a line that intersects the circle in two different points.
From the given options, the secant is XT.
A tangent is a line that intersects the circle in just one point.
From the given options, the tangent is ZW.