What is the term used to refer to the mother of a horse?

The term used to refer to the mother of a horse is "dam." In equine terminology, "dam" specifically identifies the female parent, whereas "sire" refers to the male parent. Understanding these terms is crucial in breeding and pedigree discussions, as they help clarify lineage and heritage.

A filly is a young female horse, typically under the age of three, while a gelding is a male horse that has been castrated. These terms describe the horse's age and gender rather than its parental role. Thus, "dam" accurately describes the role of a female horse in relation to her offspring, making it the correct choice.