from the GNU version of the Collaborative International Dictionary of English
- adj. Of, pertaining to, or designating, a sulphonic acid obtained, as a blue solution, by dissolving indigo in sulphuric acid; -- formerly called also cerulic sulphuric acid, but properly called indigo-disulphonic acid.
from The Century Dictionary and Cyclopedia
- Same as sulphoindigotic.
Sorry, no etymologies found.