Cut from the beef flank, the skirt steak is the diaphragm muscle (which lies between the abdomen and chest cavity). It's a long, flat piece of meat that's flavorful but rather tough. Properly cooked, skirt steak can be quite tender and delicious. It can either be quickly grilled, or stuffed, rolled and braised. Recently skirt steak has become quite fashionable because of the delicious Southwestern dish fajitas.
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.