from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A focometer; lensmeter
from the GNU version of the Collaborative International Dictionary of English
- n. An assisting instrument for focusing an object in or before a camera.
from The Century Dictionary and Cyclopedia
- n. An optical instrument for finding the focus of a lens.
Sorry, no etymologies found.
A correspondent desires to know how to test the coincidence or otherwise of the visual and actinic foci of a combination: this is very readily accomplished by the aid of a _focimeter_, which can be easily made thus: