Sirloin is a cut of beef from the lower part of a cow’s back, just above the loin. Cooks treat it as a good piece — tender enough for a steak, with a strip of fat that browns well. On a menu, sirloin means that cut, not any beef. Though actually the word does not name quite the same piece in every country: British and American butchers draw the lines in slightly different places, so a sirloin steak in London and one in New York are cousins, not twins. There is a famous story that a king liked the meat so much he made it a knight — “Sir Loin.” People still tell it, but that is not how the word was made. It comes from French for “above the loin.”