What is "pork tenderloin"

n. pork loin muscle

The pork tenderloin, in some countries called pork fillet, is a cut of pork. It is often sold as prepackaged products by large grocery stores. They are available plain (not seasoned) and flavored with a marinade.

As with all quadrupeds, the tenderloin refers to the psoas major muscle along the central spine portion, ventral to the lumbar vertebrae. This is the most tender part of the animal, because these muscles are used for posture, rather than locomotion.