eyepiece
UK: ˈaɪ.piːs | US: ˈaɪ.piːs
n. the lens or group of lenses in an optical instrument (e.g., microscope, telescope) through which the viewer looks to observe the magnified image.
The word "eyepiece" is a straightforward compound formed from "eye" (Old English ēage, meaning the organ of vision) and "piece" (Old French piece, meaning a part or segment). It emerged in the 18th century to describe the component of optical devices where the user places their eye to view the magnified image. The term reflects the functional role of this part—literally the "piece" for the "eye."
Adjust the eyepiece to focus the microscope image clearly.
The telescope’s eyepiece was scratched, distorting the view of the stars.
She replaced the standard eyepiece with a high-magnification one for detailed observation.
Clean the eyepiece gently to avoid damaging the lenses.
The binoculars’ eyepieces can be twisted to suit different users’ vision.