Tack

A tack is a turn that brings the bow of the boat through the eye of the wind. As the bow crosses, the sails switch from one side of the boat to the other. Tacking is how a sailboat works its way upwind, since no boat can sail directly into the wind — instead, you zig-zag back and forth, tacking through the no-go zone. The word also refers to which side of the boat the wind is coming over: a boat with wind on its starboard side is on starboard tack and has right of way over a port-tack boat.