Stop: The step up from muzzle to back skull; indentation between the eyes where the nasal bones and cranium meet.

Straight In Pastern: Little or no bend at the wrist.

Straight Shoulders: The shoulder blades rather straight up and down, as opposed to sloping or well laid back.

Straight-Hocked: Lacking appreciable angulation at the hock joints.

Stud Book: Monthly publication of the AKC. A listing of dogs that have sired or whelped a litter for the first time that has been registered with the AKC. With this information, a person can use Stud Book volumes to trace a dog's lineage and to produce pedigrees.

Stud Dog: A male dog used for breeding purposes.

Stud Fee: Payment made for the services of a stud dog.

Substance: Bone.

Superciliary Arches: The ridge, projection, or prominence of the frontal bones of the skull over the eyes; the brow; supraorbital ridges.

Suspension Trot: See Flying Trot

Swayback: Concave curvature of the vertebrae column between the withers and the hipbones.

Symmetry: Pleasing balance between all parts of the dog.