Ever wonder what that number on the handle of your cast-iron skillet means? It’s not, as you might think, the size of the pan. The number actually refers to the diameter of the pan in inches across the bottom of the pan, not across its flared top, which is the industry standard way to measure skillet size. So what gives? The number on the handle (and sometimes bottom) of the pan has a history: Originally, cast-iron cookware was made to fit into the openings on top of woodstoves; the same folks who made the stoves, including Griswold and Lodge, made pans that would fit into the holes positioned over the fire. That’s why even today, the item number for a 12-inch Lodge skillet is  L10SK3. According to Lodge: “The 10 comes the days from when cast-iron pots and pans were sized to fit on the numbered eyes of a woodstove. The L10SK3 was for a #10 stove eye.” So instead of trusting any numbers you may see on a skillet, trust a ruler instead-and measure across the top.