Entry 1 sense Webster, 1913 Photo- /(fō"tō̇-)/ · Pho·to- · IPA /foʊtoʊ/ 01 A combining form from Gr. fw^s, fwto`s, light; as, photography, phototype, photometer. 1. A combining form from Gr. fw^s, fwto`s, light; as, photography, phototype, photometer.