Which term refers to a mature female pig?

The term that refers to a mature female pig is "sow." This is a specific terminology used in animal husbandry to denote an adult female pig, typically one that has already given birth to at least one litter of piglets.

In the context of livestock terminology, a "heifer" refers to a young female cow that has not yet borne calves, which is distinct from pigs. An "ewe" specifies a female sheep, and as such, is not applicable to pigs either. The term "gilt" is used to describe a young female pig that has not yet had any piglets, making it different from a matured sow. Understanding these terms is important for proper animal management and breeding practices.