[rey-dee-oh-ak-tin-ee-uh m] /ˌreɪ di oʊ ækˈtɪn i əm/
the radioactive isotope of thorium having a mass number 227 and a half-life of 18.8 days. Symbol: RdAc, Th 227.
[rey-dee-oh-uh-koo-stiks] /ˌreɪ di oʊ əˈku stɪks/ noun, (used with a singular verb) 1. the science and technology of the production, transmission, and reproduction of sounds carried by radio waves.
[rey-dee-oh-ak-tuh-veyt] /ˌreɪ di oʊˈæk təˌveɪt/ verb (used with object), radioactivated, radioactivating. Physics. 1. to make (a substance) . /ˌreɪdɪəʊˈæktɪˌveɪt/ verb 1. (transitive) to make radioactive
[rey-dee-oh-ak-tiv] /ˌreɪ di oʊˈæk tɪv/ adjective, Physics, Chemistry. 1. of, pertaining to, exhibiting, or caused by . /ˌreɪdɪəʊˈæktɪv/ adjective 1. exhibiting, using, or concerned with radioactivity adj. 1898, from French radio-actif, coined by Pierre and Marie Curie from radio-, comb. form of Latin radius (see radiation) + actif “active” (see active). radioactive ra·di·o·ac·tive (rā’dē-ō-āk’tĭv) adj. […]
noun 1. . noun 1. any method of determining the age of earth materials or objects of organic origin based on measurement of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product. noun 1. another term for radiometric dating noun 1. any method of dating material based on […]