Source : Webster's Revised Unabridged Dictionary (1913)

Phenanthroline \Phe*nan"thro*line\, n. [Phenanthrene +
   quinoline.] (Chem.)
   Either of two metameric nitrogenous hydrocarbon bases,
   {C12H8N2}, analogous to phenanthridine, but more highly
   nitrogenized.