Question

parts of circles dictionary
term | definition | example or visual
circle | the set of points equidistant from center | circle drawing
radius | a segment with endpoints at the center and on the circle | circle with radius drawing
chord | a segment with both endpoints on circle | circle with chord drawing
diameter | a cord that goes through center of circle | circle with diameter drawing, d = 2r
secant | a line that intersects circle in 2 places | circle with secant line drawing
tangent | a line that touches circle at one point | circle with tangent line drawing
point of tangency | point where tangent touches circle | circle with point of tangency drawing
© gina wilson (all things algebra®, llc), 2015 - 2019

Explanation:

Since the problem (from the image) is about defining parts of circles (like circle, radius, chord, etc.), this falls under the Mathematics discipline, specifically the subfield of Geometry. If we assume a question like "What is the definition of a radius?" (a common geometry question about circle parts), here's the solution:

The radius is defined as a segment with endpoints at the center of the circle and on the circle itself. This is consistent with the given dictionary entry for "RADIUS" which states: "A segment with endpoints at the center and on the circle".

Answer:

A segment with endpoints at the center and on the circle