n. A common name of Fierasfer affinis, a fish found in the Bay of Panama, in the shells of the pearl-oyster; any fish of the family Fierasferidæ, which lives in the shells of mollusks and in large Holothuria.n. A minnow, Alburnus lucidus, and other allied species, ranging over Europe and western Asia. The pearly matter from their scales is used in the manufacture of artificial pearls.