a colorless, crystalline compound, CHO·3HO, extracted from logwood and used as an indicator and a stain in microscopy: when oxidized it yields hematein dye
See hematoxylin in American Heritage Dictionary 4
(hēˌmə-tŏkˈsə-lĭn)
noun
A yellow or red crystalline compound, C16H14O6·3H2O, the coloring material of logwood, that is used in dyes, inks, and stains.