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.
Whereas the rod conveys the concept of authority, of power, of discipline, of defense against danger, the word staff speaks of all that is longsuffering and kind. The shepherd's staff is normally a long, slender stick, often with a crook or hook on one end.