1 In this sense it is nearly synonymous with synopsis. ( 2 n.) The tracing of things to their source, and the resolving of knowledge into its original principles. ( 3 n.) A syllabus, or table of the principal heads of a discourse, disposed in their natural order.
A lightning rod or lightning conductor is a iron rod that is used to make lightning strike it, rather than strike something else. It is part of a lightning protection system. Such a system is made of many such rods. These rods are usually placed at high points of buildings and structures.
A grounding rod is a safety component of an electrical system which carries current away from a surging electrical circuit and routes it safely into the ground. Grounding rods are required for many electrical systems all over the world for safety reasons, and in regions where they are not required by law, they are in common use because they are excellent safety devices which are affordable to install.