Kosher describes food that follows Jewish dietary laws called kashrut. These ancient rules, found in the Torah, specify what foods Jewish people may eat and how those foods must be prepared. Meat must come from certain animals that have split hooves and chew their cud, like cows and sheep, but not pigs. Fish must have both fins and scales. Dairy products and meat cannot be eaten together or even prepared using the same dishes.

For food to be kosher, it must be prepared in specific ways. Animals must be slaughtered in a way that follows Jewish law by a trained specialist. A rabbi or kosher supervisor inspects food production to ensure all rules are followed. You'll see products labeled “kosher” in many grocery stores, marked with symbols like a circled K or a U, showing they've been certified.

Beyond food, people sometimes use kosher informally to mean legitimate or acceptable: “Is it kosher to bring a friend to the party?” In this sense, kosher means proper or allowed according to the rules or customs that apply.

Many people who aren't Jewish also choose kosher foods, appreciating the careful inspection and preparation standards. Kosher hot dogs, pickles, and deli foods have become American favorites far beyond their religious origins.