The Collaborative International Dictionary of English v.0.48:

Picoline \Pic"o*line\, n. [L. pix, picis, pitch + oleum oil +
   -ine.] (Chem.)
   Any one of three isometric bases (C6H7N) related to
   pyridine, and obtained from bone oil, acrolein ammonia, and
   coal-tar naphtha, as colorless mobile liquids of strong odor;
   -- called also methyl pyridine.
   [1913 Webster]