eyeball

UK: ˈaɪbɔːl | US: ˈaɪbɔːl

Definition
  1. n. the round part of the eye, including the iris and pupil, enclosed by the eyelids

  2. vt. to stare at or observe closely (informal)

Structure
eye <organ of vision>ball <spherical object>
Etymology

The word "eyeball" is a straightforward compound formed from "eye" (Old English ēage, meaning the organ of vision) and "ball" (Old English bealla, meaning a rounded object). It emerged in Middle English (circa 13th century) as a literal descriptor for the spherical shape of the eye. The verb form, meaning "to scrutinize," arose in 20th-century slang, leveraging the visual intensity implied by the noun.

Examples
  1. The doctor examined her eyeball for signs of infection.

  2. He eyeballed the stranger suspiciously across the room.

  3. The cartoon character’s eyeballs popped out in exaggerated surprise.

  4. She carefully eyeballed the measurements before cutting the fabric.

  5. The robot’s cameras mimicked the movement of human eyeballs.