The Collaborative International Dictionary
photogene
Photogen \Pho"to*gen\, n. [Photo- + -gen.] (Chem.) A light hydrocarbon oil resembling kerosene. It is obtained by distilling coal, paraffin, etc., and is used as a lubricant, illuminant, etc. [Written also photogene.]
Wiktionary
photogene
n. 1 (context obsolete English) A photograph 2 (context dated English) An afterimage 3 (context genetics English) A gene involved in photosynthesis