Shadowgraph

Part of speech: noun

Definitions

1. A technique for creating images that highlights the outlines of objects by using light and shadow, effectively illustrating their forms and contours
2. An imaging process that employs light to cast silhouettes of objects onto a surface, showcasing their shapes and features
3. A method of producing images that captures the shapes of objects by using contrasting light and dark areas to portray their outlines and details

Etymology: A shadowgraph is a picture made without a lens or camera: an object is placed between a light source and a surface, and the shadow it casts is the image. The name is a plain compound of "shadow" and the combining element "-graph", which comes from the Greek "gráphō", meaning "to write" or "to draw". So the word literally describes a drawing made by shadow. The "-graph" element is the same one found in "photograph", "telegraph" and "autograph", where it means a written or drawn record. Because "shadow" in English is an old native word, the only classical part of "shadowgraph" is the suffix, which was attached to it in the way many modern technical terms were built. The date of its first English use is not something I can confirm here, though the formation is transparent enough that the word's meaning follows directly from its parts.