In an electric system to protect underground iron pipes or structures from electrochemical action, a metallic rod which is driven […]

1. A signaling device, usually electrically operated, that emits an audible signal and/or a visual indication under selected circumstances; for

A shaft or cluster of shafts fitted, at intervals, with rings.

A nail with circular ridges around its shaft; provides greater holding power than a nail without such ridges.

Said of a ring-shaped structure or object.

A layer of wood produced during one year of a trees growth.