<p><strong>Noun</strong></p><ul><li>Wilhelm Konrad (1845–1923): German physicist, discoverer of x-rays (1895), Nobel Prize (1901)</li><li>Physics: a unit of exposure dose that measures x-rays or gamma rays in terms of the ions or electrons produced in dry air at 0° C and one atmosphere, equal to the amount of radiation producing one electrostatic unit of positive or negative charge per cubic centimeter of air; symbol: r, R</li></ul><p><strong>Adjective</strong></p><ul><li>(sometimes lowercase) of or relating to Wilhelm Roentgen, the Roentgen unit, or especially to x-rays</li></ul>