what is a mare in horse terms

In horse terms, a mare is an adult female horse or other equine. In most cases, a mare is a female horse over the age of three. Mares are used in every equestrian sport and usually compete equally with stallions and geldings in most events, though some competitions may offer classes open only to one sex of horse or another, particularly in breeding or "in-hand" conformation classes. In horse racing, mares and fillies have their own races and only a small percentage compete against male horses.