from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Having normal vision; free from visual distortion.
- adj. Giving an undistorted image. Used of an optical instrument.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. free from optical distortion
from the GNU version of the Collaborative International Dictionary of English
- adj. Giving an image in correct or normal proportions; giving a flat field of view.
from The Century Dictionary and Cyclopedia
- Seeing correctly; having normal vision.
- Constructed so as to present surrounding objects correctly to the eye: as, an orthoscopic eyepiece or ocular.
- Presented in its normal appearance to the eye: as, an orthoscopic image.
ortho- + -scopic (Wiktionary)