Pronunciation: (fō'tō), [key]
2. Informal.See photo finish.
a combining form meaning “light” (photobiology); also used to represent “photographic” or “photograph” in the formation of compound words: photocopy. Also, esp. before a vowel,phot-.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.