Atrament

Atramentum or atrament, generally means a very black, usually liquid, substance. For example, an octopus may emit a puff of atrament (see cephalopod ink).
In ancient Rome, the term atramentum signified any black colouring substance used for any purpose. The Romans distinguished three principal kinds of atramentum, one called librarium (or scriptorium), another called sutorium, the third tectorium.
Atramentum librarium was the writing ink of Roman times, atramentum sutorium was used by shoemakers for dyeing leather, and atramentum tectorium (or... meer