👉 In mathematics, a semidisk is a subset of the complex plane that does not intersect itself. It can be defined as a disk or an annulus with two arms, where one arm is parallel to the real axis and the other arm is parallel to the imaginary axis. The term "semidisk" is often used in connection with the concept of "semicircle" in geometry, which refers to any circle that intersects itself at exactly one point. However, it can also refer to