from The American Heritage® Dictionary of the English Language, 4th Edition
- Light; radiant energy: photosynthesis.
- Photographic: photomontage.
- Photoelectric: photoemission.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- light, electromagnetic radiation
from the GNU version of the Collaborative International Dictionary of English
- A combining form from Gr. fw^s, fwto`s, light.
Greek phōto-, from phōs, phōt-; see bhā-1 in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)
From the combining form φωτ- (phōt-) of Ancient Greek φῶς (phōs, "light"). (Wiktionary)