The loins are the sides between the lower ribs and pelvis, and the lower part of the back. It is often used when describing the anatomy of Humans and quadrupeds (such as horses, pigs or cattle). The anatomical reference also carries over into the description of cuts of meat from some such animals, eg. tenderloin or sirloin steak.
In the Authorized King James Version the term "loins" is used frequently. It is suggested that the "loins" is the minimum one must cover on their body to be respectful of the law. This suggests that if a man (or possibly woman as well) covers up just their genital area, they are considered clothed enough for public life. Frequently the term The Fruit of His Loins is used to refer to children. Such a fruit of my loins reference is also made in the King James Version.
Butchers frequently refer to the section of meat below the rib cage, yet above the round as loin. Various names of meats further butchered from the loin section of cattle and pork contain the name "loin" such as tenderloin and sirloin. In American Culinary arts the loin section of meat from the top half of cattle is divided into three sections. The various names for the cuts of beef from this section are named sirloin, tenderloin, top sirloin, and short loin. They are named for their respective parts on the cattle. In England's Culinary art system, the loin section of beef is generally only registered as one part, instead of the American three. While the many sections of loin are available in England, it is generally considered one cut.
It has been suggested by many culinary professionals that tenderloin is the most tender cut of beef one can get. The loin section of beef is fairly popular among consumers for its low fat qualities. It is also the source of the highly desirable filet mignon.