The Collaborative International Dictionary of English v.0.48:
Iron-gray \I"ron-gray`\, a. Of a gray color, somewhat resembling that of iron freshly broken. -- n. An iron-gray color; also, a horse of this color. [1913 Webster]WordNet (r) 3.0 (2006):
iron-gray adj 1: of the grey color of iron [syn: iron-grey, iron-gray] n 1: the color of freshly broken cast iron [syn: iron-grey, iron-gray]