Contrary to popular belief, Châteaubriand is actually a recipe, not a cut of beef. This method of preparation is said to be named for the 19th-century French statesman and author, François Châteaubriand. It's a succulent, thick cut of beef (usually taken from the center of the tenderloin) that's large enough for two people. The Châteaubriand is usually grilled or broiled and served with béarnaise and château potatoes (trimmed into olive shapes and sautéed in butter). See also short loin.
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.