Pearl oyster

Pearl Pearl, n. [OE. perle, F. perle, LL. perla, perula, probably fr. (assumed) L. pirulo, dim. of L. pirum a pear. See {Pear}, and cf. {Purl} to mantle.] 1. (Zo["o]l.) A shelly concretion, usually rounded, and having a brilliant luster, with varying tints, found in the mantle, or between the mantle and shell, of certain bivalve mollusks, especially in the pearl oysters and river mussels, and sometimes in certain univalves. It is usually due to a secretion of shelly substance around some irritating foreign particle. Its substance is the same as nacre, or mother-of-pearl. Pearls which are round, or nearly round, and of fine luster, are highly esteemed as jewels, and compare in value with the precious stones. [1913 Webster]

2. Hence, figuratively, something resembling a pearl; something very precious. [1913 Webster]

I see thee compassed with thy kingdom's pearl. --Shak. [1913 Webster]

And those pearls of dew she wears. --Milton. [1913 Webster]

3. Nacre, or mother-of-pearl. [1913 Webster]

4. (Zo["o]l.) A fish allied to the turbot; the brill. [1913 Webster]

5. (Zo["o]l.) A light-colored tern. [1913 Webster]

6. (Zo["o]l.) One of the circle of tubercles which form the bur on a deer's antler. [1913 Webster]

7. A whitish speck or film on the eye. [Obs.] --Milton. [1913 Webster]

8. A capsule of gelatin or similar substance containing some liquid for medicinal application, as ether. [1913 Webster]

9. (Print.) A size of type, between agate and diamond. [1913 Webster] [hand] This line is printed in the type called pearl. [1913 Webster]

{Ground pearl}. (Zo["o]l.) See under {Ground}.

{Pearl barley}, kernels of barley, ground so as to form small, round grains.

{Pearl diver}, one who dives for pearl oysters.

{Pearl edge}, an edge of small loops on the side of some kinds of ribbon; also, a narrow kind of thread edging to be sewed on lace.

{Pearl eye}, cataract. [R.]

{Pearl gray}, a very pale and delicate blue-gray color.

{Pearl millet}, Egyptian millet ({Penicillaria spicata}).

{Pearl moss}. See {Carrageen}.

{Pearl moth} (Zo["o]l.), any moth of the genus {Margaritia}; -- so called on account of its pearly color.

{Pearl oyster} (Zo["o]l.), any one of several species of large tropical marine bivalve mollusks of the genus {Meleagrina}, or {Margaritifera}, found in the East Indies (especially at Ceylon), in the Persian Gulf, on the coast of Australia, and on the Pacific coast of America. Called also {pearl shell}, and {pearl mussel}.

{Pearl powder}. See {Pearl white}, below.

{Pearl sago}, sago in the form of small pearly grains.

{Pearl sinter} (Min.), fiorite.

{Pearl spar} (Min.), a crystallized variety of dolomite, having a pearly luster.

{Pearl white}. (a) Basic bismuth nitrate, or bismuth subchloride; -- used chiefly as a cosmetic. (b) A variety of white lead blued with indigo or Berlin blue. [1913 Webster]