Try Our Apps


Gobble up these 8 terms for eating


a combining form meaning “light” (photobiology); also used to represent “photographic” or “photograph” in the formation of compound words:
Also, especially before a vowel, phot-.
Origin of photo-
< Greek, combining form of phôs (genitive phōtós) Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
Cite This Source
British Dictionary definitions for photo-


combining form
of, relating to, or produced by light: photosynthesis
indicating a photographic process: photolithography
Word Origin
from Greek phōs, phōt- light
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
Word Origin and History for photo-

word-forming element meaning "light" or "photographic" or "photoelectric," from Greek photo-, comb. form of phos (genitive photos) "light," from PIE root *bha- "to shine" (see phantasm).

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
photo- in Medicine

photo- or phot-

  1. Light; radiant energy: photosynthesis.

  2. Photographic: photofluorography.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source
photo- in Science
A prefix that means "light," as in photoreceptor.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
Cite This Source

Word of the Day

Word Value for photo

Scrabble Words With Friends

Nearby words for photo-