noun
1. or load waterline
a. : the line on the outside of a ship to which it sinks in the water when loaded or safely loaded
b. also load line mark : a mark representing the safe load line
2. : one of a set of marks graduated in accordance with international standards and required by law in most maritime countries to be cut and painted amidships on the sides of a seagoing cargo ship to indicate the greatest draft to which it can be safely loaded under various conditions (as tropical fresh water or North Atlantic winter) — see plimsoll mark