The oxtail was once really from an ox but nowadays the term generally refers to beef or veal tail. Though it's quite bony, this cut of meat is very flavorful. Because it can be extremely tough (depending on the age of the animal), oxtail requires long, slow braising. It's often used for stews or soups such as the hearty English classic oxtail soup, which includes vegetables, barley and herbs and is often flavored with sherry or madeira. See also variety meats.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.