What do you call a mature male animal in equine terminology?

In equine terminology, a mature male horse is specifically termed a stallion. This term signifies not only the age of the animal but also its maturity and reproductive status. Stallions are known for their distinct physical and behavioral characteristics, including a more muscular build and a tendency to be more aggressive or dominant, particularly when in the presence of other males or during breeding season.

The other terms listed refer to different animal species or categories. A tom is a mature male cat, a doe refers to a female deer or rabbit, and an ewe is a female sheep. Thus, stallion is the correct terminology when referring to a mature male within the context of equines.