n. 珠母贝, 真珠质

[ noun ]
the iridescent internal layer of a mollusk shell
<noun.substance>

Nacre \Na"cre\ (n[=a]"k[~e]r), n. [F., cf. Sp. n['a]cara,
n['a]car, It. nacchera, naccaro, LL. nacara, nacrum; of
Oriental origin, cf. Ar. nak[=i]r hollowed.] (Zo["o]l.)
A pearly substance which lines the interior of many shells,
and is most perfect in the mother-of-pearl. [Written also
{nacker} and {naker}.] See {Pearl}, and {Mother-of-pearl}.