Black's Law Dictionary (2nd edition)dictionaries

A Rubro Ad Nigrum

Lat. From the red to the black; from the rubric or title of a statute, (which, anciently, was in red letters,) to its body, which was in the ordi-nary black. Tray. Lat Max.; Bell, “Ru-bric.”

Source: Black's Law Dictionary 2nd Ed (1910)