Post #3792714

Is there an English word for "the thing from which a shadow is being cast"? For example, when looking at a shadow of a particular tree, you could say "The shadow's foo", and your interlocutor would understand that "foo" refers to a particular tree, specifically in the tree's role of being the thing that -- along with the Sun as light source -- is responsible for the shadow that is already a common reference point in the conversation? If not in English, does anyone know of such a word in another language?