noun🔗ShareActinideAny of the 14 radioactive elements of the periodic table that are positioned under the lanthanides, to which they have similar chemistry."Uranium, an actinide, is a heavy metal used in some power plants. "L'uranium, un actinide, est un métal lourd utilisé dans certaines centrales électriques.elementchemistryscienceChat with AIVocabulary GamePractice Reading
