What is the term for a female horse?

The term for a female horse is "mare." This designation is used specifically for adult female horses, typically over the age of three. It is important to note that a filly refers to a young female horse that is not yet mature, while a gelding is a castrated male horse. The term "cow" refers to a female of the cattle species and is not applicable to horses. Understanding these terms is crucial in the context of equine management and breeds, as it helps differentiate between the various classifications within equine species.