Alternative term: Spherical Mirror
A type of mirror the reflecting surface of which is a portion of a sphere. Light rays emitted by a point source placed at the centre of the sphere are returned through the centre. Such mirrors are usually used as reinforcing mirrors.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM