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. (Zool.) 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 at one time compared in value with the precious stones. Since development of cultured pearls, the relative value has diminished somewhat, though the best pearls are still expensive, and natural pearls even more so. Artificial pearls may be made of various materials, including material similar to that of natural pearls; these are less expensive than natural or cultured pearls. See cultured pearl, below. [ 1913 Webster +PJC ]

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. (Zool.) A fish allied to the turbot; the brill. [ 1913 Webster ]

5. (Zool.) A light-colored tern. [ 1913 Webster ]

6. (Zool.) 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 ]

☞ This line is printed in the type called pearl. [ 1913 Webster ]

Ground pearl. (Zool.) 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 (Zool.), any moth of the genus Margaritia; -- so called on account of its pearly color. --
Pearl oyster (Zool.), 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. --
cultured pearl, a pearl grown by a pearl oyster into which a round pellet has been placed, to serve as the seed for more predictable growth of the pearl. The pellet is usually made from mother-of-pearl, and additional layers of nacre are deposited onto the seed by the oyster. Such pearls, being more easily obtained than natural pearls from wild oysters, are less expensive. [ 1913 Webster ]

v. t. 1. To set or adorn with pearls, or with mother-of-pearl. Used also figuratively. [ 1913 Webster ]

2. To cause to resemble pearls; to make into small round grains; as, to pearl barley. [ 1913 Webster ]

v. i. 1. To resemble pearl or pearls. [ 1913 Webster ]

2. To dive or hunt for pearls; as, to go pearling. [ 1913 Webster ]

a. Of or pertaining to pearl or pearls; made of pearls, or of mother-of-pearl. [ 1913 Webster ]

n. A fringe or border. [ Obs. ] -- v. t. To fringe; to border. [ Obs. ] See Purl. [ 1913 Webster ]

Pearl stitch. See Purl stitch, under Purl. [ 1913 Webster ]

a. Resembling pearl or mother-of-pearl; pearly in quality or appearance.
Syn. -- iridescent, nacreous, opalescent, opaline, pearlaceous. [ 1913 Webster ]

n. (Chem.) A white amorphous or granular substance which consists principally of potassium carbonate, and has a strong alkaline reaction. It is obtained by lixiviating wood ashes, and evaporating the lye, and has been an important source of potassium compounds. It is used in making soap, glass, etc. [ 1913 Webster ]

n. A diver who searches for molluscs containing pearls; a pearl diver.
Syn. -- pearl diver. [ WordNet 1.5 ]

pos>adj. 1. Having an iridescent pearl-like surface, giving a play of lustrous rainbowlike colors; nacreous; pearlaceous.
Syn. -- iridescent, nacreous, opalescent, opaline, pearlaceous. [ WordNet 1.5 ]

a. Having a pearly speck in the eye; afflicted with a cataract or cataracts. [ 1913 Webster ]