from
The Collaborative International Dictionary of English v.0.48
radiograph \ra"di*o*graph\ (r[=a]"d[i^]*[-o]*gr[a^]f), n.
[Radio- + -graph.]
1. An instrument for measuring and recording solar radiation.
[Webster 1913 Suppl.]
2. An image or picture produced upon a sensitive surface, as
of a photographic or fluorescent plate, by some form of
penetrating radiation other than light, as X-rays, beta
rays, etc.; esp., a picture of the internal structure of
opaque objects traversed by the rays; a skiagraph. When
the picture is produced upon photographic film by X-rays,
the picture is usually called an {X-ray photo} or {X-ray}.
When an image is produced on photographic film by a
radioactive substance in close proximity to the film, in a
manner so as to record the spatial distribution of the
radioactive substance, the resulting image is called an
{autoradiograph} or {{autoradiogram}}.
[Webster 1913 Suppl. +PJC]