Source : Webster's Revised Unabridged Dictionary (1913)

Ferruginous \Fer*ru"gi*nous\, a. [L. ferruginus, ferrugineus,
   fr. ferrugo, -ginis, iron rust: cf. F. ferrugineux. See
   {Ferrugo}.]
   1. Partaking of iron; containing particles of iron. --Boyle.

   2. Resembling iron rust in appearance or color; brownish red,
      or yellowish red.