Overview
The loins, or lumbus, are the sides between the lower ribs and pelvis, and the lower part of the back. The term is used to describe the anatomy of humans and quadrupeds, such as horses, pigs, or cattle. The anatomical reference also applies to particular cuts of meat, including tenderloin or sirloin steak.
Human anatomy
In human anatomy the term "loin" or "loins" refers to the side of the human body below the rib cage to just above the pelvis. It is frequently used to reference the general area below the ribs. While the term "loin" is generally not used in medical science, some disorders do include the term.
The lumbar region of the spinal column is located in the loin area of the body.
Society and culture
In contemporary usage the term appears primarily in two contexts: where loins are "girded" in preparation for a challenge, or else euphemistically referring to human genitals. In literature or poetry, to feel a "stirring" in one's loins may suggest sexual excitement.
From Wikipedia (CC BY-SA 4.0).