| mergus | (n) mergansers, Syn. genus Mergus |
| fergusonite | (n) a dark mineral consisting of oxides of yttrium and erbium and tantalum and other minerals |
| Mergus | prop. n. A genus of ducks consisting of mergansers. |
| Fergusonite | n. (Min.) A mineral of a brownish black color, essentially a tantalo-niobate of yttrium, erbium, and cerium; -- so called after Robert Ferguson. [ 1913 Webster ] |
| fergus |