a smooth, rounded bead formed within the shells of certain mollusks and composed of the mineral aragonite or calcite in a matrix, deposited in concentric layers as a protective coating around an irritating foreign object: valued as a gem when lustrous and finely colored. Compare cultured pearl.
something resembling this, as various synthetic substances for use in costume jewelry.
something similar in form, luster, etc., as a dewdrop or a capsule of medicine.
something precious or choice; the finest example of anything: pearls of wisdom.
a very pale gray approaching white but commonly with a bluish tinge.