indolineChem.|ˈɪndəʊlaɪn| [f. indole + -ine.] A polymer of indole, C16H14N2, formed by heating leucindigo with barium hydrate, zinc-dust, and water, crystallizing in long bright yellow needles. 1884in Cassell's Encycl.Dict.1892in Morley & Muir Dict.Chem. II. 760.