Estray

Definition of Estray

An estray is an animal that has escaped from its owner, and wanders or strays about; usually defined, at common law, as a wandering animal whose owner is unknown. An animal cannot be an estray when on the range where it was raised, and permitted by its owner’to run, and especially when the owner is known to the party who takes it up.

The term is also used of flotsam at sea.

That's the definition of Estray in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.