Answer:
Chords: A chord of a circle is a segment that you draw from one point on the circle to another point on the circle.
Tangent: A tangent to a circle is a line, ray, or segment that touches the outside of the circle in exactly one point.
Explanation:
A chord always stays inside the circle. The largest chord possible is the diameter — you can’t get any longer than that segment.
It never crosses into the circle. A tangent can’t be a chord, because a chord touches a circle in two points, crossing through the inside of the circle. Any radius drawn to a tangent is perpendicular to that tangent.