[ foh-toh ]
/ ˈfoʊ toʊ /

noun, plural pho·tos.

Origin of photo

First recorded in 1855–60; shortened form of photograph

Definition for photo (2 of 2)


a combining form meaning “light” (photobiology); also used to represent “photographic” or “photograph” in the formation of compound words: photocopy.
Also especially before a vowel, phot-.

Origin of photo-

<Greek, combining form of phôs (genitive phōtós) Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for photo (1 of 2)

/ (ˈfəʊtəʊ) /

noun plural -tos

British Dictionary definitions for photo (2 of 2)


combining form

of, relating to, or produced by lightphotosynthesis
indicating a photographic processphotolithography

Word Origin for photo-

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

Medical definitions for photo



Light; radiant energy:photosynthesis.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for photo


A prefix that means “light,” as in photoreceptor.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.