(Science: zoology) A pearly substance which lines the interior of many shells, and is most perfect in the mother-of-pearl.
Alternative forms: nacker and naker See pearl, and mother-of-pearl.
Origin: F, cf. Sp. Nacara, nacar, It. Nacchera, naccaro, LL. Nacara, nacrum; of Oriental origin, cf. Ar. Nakir hollowed.