i Register
In some senses, estray is marked as archaic. Watch for register when choosing this word.
noun
An animal that has escaped from its owner; 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. A lost animal whose owner is known to the party at
Stray.
[...] All the day / Had been a dreary one at best, and dim / Was settling to its close, yet shot one grim / Red leer to see the plain catch its estray.
verb
To stray.
With other Maids to fiſh upon the Shoar; Estrays apart, and leaves her Company