The correct answer is D) casting fitted at the side of a deck used as a fairlead. A chock is a deck fitting used to guide and secure mooring lines, anchor cables, and other lines passing over the side of a vessel. It is typically a metal casting or fitting installed at the side of the deck to provide a smooth, angled surface to direct the line and prevent excessive wear or chafing. This definition matches answer choice D, making it the correct answer. The other answer choices do not accurately describe what a chock is. A smoke pipe from a galley stove (B) and a wooden block to support cargo (C) are different types of fittings or equipment, not the specific definition of a chock.