1. A thin plate, scale, membrane, or layer, as of bone, tissue, or cell walls.
2. A thin scale, plate, or layer of bone or tissue, as in the gills of a bivalve mollusk or around the minute vascular canals in bone.
3. In mosses, a thin sheet of cells standing up along the midrib of a leaf.
4. In building trades, a member of wood, metal, or reinforced concrete, joined in a crisscross pattern with other lamellae to form a vault.
5. In ophthalmology, a small disk of gelatin and glycerin mixed with a medicinal substance, used as a medicament for the eyes.

From Latin, lamina, lammina, or lamna; a plate or thin piece of wood, metal, marble, a saw blace, or the thin shell of fruit.

1. One of a varying number of layers of bone encircling either the external surface of compact bone (lamella circumferentialis externa) or the internal surface lining the wall of the narrow cavity (lamella circumferentialis interna).
2. A thin layer of bone that is deposited under the periosteum (membrane that covers the outer surface of all bones) or the endosteum (thin vascular membrane of connective tissue that lines the surface of the bony tissue) that forms the medullary (soft substance) cavity of long bones