Isatin \I"sa*tin\, n. [See {Isatis}.] (Chem.)
An orange-red crystalline substance, {C8H5NO2}, obtained by
the oxidation of indigo blue. It is also produced from
certain derivatives of benzoic acid, and is one important
source of artificial indigo. [Written also, less properly,
{isatine}.]
[1913 Webster]