Literally meaning: “tendency to light”
Origin: Anc Greek
φως/phos(=light) > (in the genitive) φωτός/photos(=of light)
+-τρόπος/tropos(=suffix denoting way, habit, direction or tendency) >τρέπω/trepo(=turn)
Phototropism is the tendency of an organism to turn or direct its growth in response to a light source.