Kosher salt usually has no additives, and it has big crystals with large surface areas. This size and shape allows it to absorb more moisture than other forms of salt, and this makes kosher salt excellent for curing meats. That is essentially where the name comes from. The salt itself is not kosher, meaning it doesn't conform to Jewish food laws, but this salt is used to make meat kosher. The Jewish holy book, the Torah, prohibits consumption of any blood, which is why kosher meat must be slaughtered and prepared in a specific manner. A common way of removing the final traces of blood from meat is to soak and salt it.
That's not the only use for kosher salt, however. The flavor is distinct from ordinary table salt, and some cooks prefer to use it in all their cooking. Like other coarse salts, kosher salt can be used in recipes that call for a salt crust. You can even use it to salt the edge of a margarita glass.
