a. [f. L. ferrūgin-, ferrūgō iron rust (f. ferrum iron) + -OUS. Cf. F. ferrugineux.
The use 1 b, which exists also in Fr., is due to the word being referred directly to the L. ferrum, as if its formation were analogous to that of oleaginous, etc.]
1. a. Originally: Of or pertaining to, of the nature of, iron rust; containing iron rust (said esp. of mineral springs, earths, etc.). b. Now commonly: Of the nature of iron as a chemical element; containing iron as a constituent.
a. 1661. Fuller, Worthies, Bristol, III. 34. The Water thereof runneth through some Mineral of Iron, as appeareth by the rusty ferruginous taste.
1684. Boyle, Mineral Waters, Wks. 1772, IV. 798. Mineral waters, especially ferruginous ones.
1792. A. Young, Trav. France, 290. Franche Compté abounds with red ferruginous loams.
1810. T. Thomson, A System of Chemistry (ed. 4), II. 376. Ferruginous prussiate of potash, then, is the substance usually employed as a reagent.
1816. W. Smith, Strata Ident., 12. Sand concreted by a ferruginous cement.
1834. Mrs. Somerville, Connex. Phys. Sc., xxx. (1849), 352. A ferruginous body acquires polarity.
1871. Blackie, Four Phases, i. 122. The type of any race of animals is not to be taken from monsters, nor is the law of the variations of the magnetic needle near ferruginous rocks or in an iron vessel to be paraded as a proof that there is no such thing as magnetic polarity.
1871. Daily News, 21 Sept. A very insignificant ferruginous spring was the only one they came across.
2. Resembling iron-rust in color; reddish brown.
1656–81. Blount, Glossogr., Ferruginous … of the colour of rusty iron.
1766. Pennant, Zool. (1768), I. 104. The whole upper part of the body [of the short tailed mouse] is of a ferruginous color, mixed with black.
1789. Mills, in Phil. Trans., LXXX. 93. The water … tinges the sides of a ferruginous hue.
1870. Hooker, Stud. Flora, 462. Rootstock stout, ascending, often 6–8 in., clothed with broad ferruginous scales.
b. In the names of animals, plants or minerals.
1847. Craig, Ferruginous opal, or Jasper opal.
1861. Miss Pratt, Flower. Pl., V. 95. Ferruginous Sallow.
1876. Smiles, Sc. Natur., xv. (ed. 4), 259. The Ferruginous … and the Eider duck visit the loch occasionally in winter.
Hence Ferrugrinousness.
1727. in Bailey, vol. II.
