Shadowgraph and X ray

Shadowgraph noun - A photographic image produced on a radiosensitive surface by radiation other than visible light (especially by X-rays or gamma rays).

X ray and shadowgraph are semantically related. In some cases you can replace phrase "X ray" with "Shadowgraph", this terms are similar.

X ray noun - A radiogram made by exposing photographic film to X rays; used in medical diagnosis.

Shadowgraph and X ray are semantically related. Sometimes you can use "Shadowgraph" instead a noun phrase "X ray".