n. A believer in the doctrine of William Miller (d. 1849), who taught that the end of the world and the second coming of Christ were at hand. [ 1913 Webster ]

n. [ From W. H. Miller, of Cambridge, Eng. ] (Min.) A sulphide of nickel, commonly occurring in delicate capillary crystals, also in incrustations of a bronze yellow; -- sometimes called hair pyrites. [ 1913 Webster ]