Otter Tail: Thick at the root, round, and tapering, with the hair parted or divided at the underside.

Out At The Elbows: Elbows turning out from the body as opposed to being held close.

Out At The Shoulders: With shoulder blades loosely attached to the body, leaving the shoulders jutting out in relief and increasing the breadth of the front.

Outcrossing: The mating of unrelated individuals of the same breed.

Oval Chest: Chest deeper than wide.

Oval Eye: As seen in Poodles, an eye with an egg shape.

Ovaries: The usually paired female or hermaphroditic reproductive organ that produces ova and, in vertebrates, estrogen and progesterone.

Overage Dam: A dam over 12 years of age on the date of mating.

Overage Sire: A sire over 12 years of age on the date of mating.

Overhang: A heavy or pronounced brow.

Overreaching: Fault in the trot caused by more angulation and drive from behind than in front so that the rear feet are forced to step to one side of the forefeet to avoid interfering or clipping.

Overshot: The incisors of the upper jaw projecting beyond the incisors of the lower jaw, thus resulting in a space between the respective inner and outer surfaces.

Ovulate: To produce ova; discharge eggs from the ovary.