Plural form of lamella, 1. An organ, process, or part resembling a plate as one of the bony concentric layers surrounding the haversian canals in bone or one of the incremental layers of cementum laid down in a tooth. 2. A thin sheetlike organic structure in the enamel of a tooth extending inward from a surface crack. 2. A small medicated disk prepared from gelatin and glycerin for use especially in the eyes.