- chlorine [klôr′ēn΄, klôr′in]n.[< Gr chlōros, pale green (< IE * ghlō-, var. of base * ghel-: see YELLOW) + -INE3: so named (1810) by DAVY Sir Humphry, who proved it to be an element, for its color]a greenish-yellow, poisonous, gaseous chemical element, one of the halogens, having a disagreeable odor and obtained by electrolysis of certain chlorides: it is used as a bleaching agent, in water purification, in various industrial processes, etc.: symbol, Cl; at. no., 17: see the periodic table of elements in the Reference Supplement
English World dictionary. V. Neufeldt. 2014.