1) DNA-binding substance 
Phenanthridine is a nitrogen heterocyclic compound that is the basis of DNA-binding fluorescent dyes through intercalation. Examples of such dyes are ethidium bromide and propidium iodide. Acridine is an isomer of phenanthridine. Phenanthridine was discovered by Amé Pictet and H. J. Ankersmit in 1891 by pyrolysis of the condensation product of be...
• (n.) A nitrogenous hydrocarbon base, C13H9N, analogous to phenanthrene and quinoline.
Phe·nan'thri·dine noun [ Phenanthr ene + pyr idine .] (Chemistry) A nitrogenous hydrocarbon base, C 13 H 9 N, analogous to phenanthrene and quinoline.