Let’s go sailing, sailing over the bounding main. A mainstay is a strong rope that helps stabilize a ship’s main mast, but for most of us mainstay means “the most important part of something; someone or something that provides primary support,” as in “The Union-Triune is a mainstay of our San Diego community.” In the same fleet as mainstay sails flagship, a ship that carries the commander’s flag and has come to mean “the best and most important of a group.” For old salts and ancient mariners, by and large was a command that meant “to sail slightly off the wind,” in contrast to full and by, “keeping the sails full of all the wind possible.” When we say by