The spelling of the word "bulls eyne" is an archaic form of the modern English word "bull's eye." The IPA phonetic transcription for this word is /bʊlz ˈaɪ/. The spelling "eyne" is a plural form of the word "eye", common in Middle English. However, this spelling is uncommon in contemporary English, and "eye" instead is used both as singular and plural forms. The modern spelling of the word is traced back to the 16th to 17th centuries, and it refers to the central target on a shooting range, and occasionally a descriptive term for a small circular object.
The term "bulls eyne" is an archaic form of "bull's eyes" and can be traced back to Middle English. The word "bull" originally referred to an adult male bovine, while "eye" referred to the organ of sight.
The term "bull's eye" was used to describe a small circular glass window or lens set into a ship's deck or into a brick wall. These windows were thick and usually convex, resembling the shape of an eye. The convex shape allowed light to enter while minimizing the amount of water or wind that could pass through. It was often used in ships to bring light into the lower deck, where there were no other openings.
Over time, "bull's eyes" began to be used metaphorically to describe things that were centrally located or marked by a distinctive target-like appearance.