Which term describes a mature female dog?

The term that describes a mature female dog is "bitch." In animal terminology, the word "bitch" specifically refers to an adult female dog, setting it apart from the terms used for female animals of other species. The use of this term is standard in canine breeding and veterinary contexts.

In contrast, "queen" refers to a mature female cat, "jill" is the term for a female ferret, and "sow" describes a female pig. Each of these terms pertains to different species, highlighting the importance of using the correct terminology to avoid confusion when discussing various animals. Thus, the use of "bitch" accurately identifies the mature female dog in this context.