from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Having multiple lenses that have corresponding focal points in the same plane
from the GNU version of the Collaborative International Dictionary of English
- adj. With the lower focal points all in the same plane; -- said of sets of eyepieces so mounted that they may be interchanged without varying the focus of the instrument (as a microscope or telescope) with which they are used.
from The Century Dictionary and Cyclopedia
- With the lower focal points all in the same plane: said of interchangeable eyepieces, for microscopes or telescopes, so mounted that whichever one is used the focus remains the same. See eyepiece.
Sorry, no etymologies found.