Correct. But it doesn’t need to be exactly half a sphere to be called a spherical mirror. You can get a mirror based on a bigger sphere that is cut down in diameter, so the focal point is in front of the actual mirror edge. The focal point hasn’t moved, but parts of the mirror is gone. But if you want to be very specific, I guess the correct terminology for this is effective focal length, as it is listed here: https://www.edmundoptics.com/optics/optical-mirrors/focusing-concave-mirrors/concave-spherical-mirrors/