photo: [19] Greek phōs meant ‘light’ (it was related to Sanskrit bhā- ‘shine’). Its stem form phōto- was used by the astronomer Sir John Herschel in 1839 to coin the term photograph, based on the Greek element -graphos ‘writing’, and perhaps inspired by a parallel German formation photographie which had appeared a little earlier the same year. The word’s living connection with the concept ‘light’ has now been virtually severed, but it still flourishes in, for example, photoelectric [19], photometer [18], photon [20], and photosynthesis [19]. => phosphorus, photon
