roentgeno-

Also röntgeno‑

X-rays.

From the name of Wilhelm Conrad Röntgen (1845–1923), the German physicist who discovered X-rays.

This form is now largely restricted to the US and even there terms are often replaced by equivalents. Examples include roentgenology, another term for radiology; roentgenography, X-ray photography, which produces a roentgenogram. Spellings using the umlaut are rare.