An incomplete male.
a colt with undescended testicles
A male equine with one testicle.
a horse with one nut.
A male horse with one or both testicles which, after July 1 of its yearling year, are not palpable in their entirety below the external inguinal ring.
A male horse with one or both testicles not descended into the scrotal sac.
A horse with only one (or none) of his testicles dropped down.