Question

what is the name of this figure?

Explanation:

A figure with two endpoints (H and I) and a straight line segment between them is called a line segment. A line segment is defined as a part of a line that is bounded by two distinct endpoints, and contains every point on the line between its endpoints. Here, the figure has endpoints H and I, so it's a line segment, specifically named segment HI (or $\overline{HI}$).

Answer:

Line segment HI (or $\overline{HI}$)