scale ¹ (skāl)

1. A dry, thin flake of epidermis shed from the skin.
2. One of the many small, platelike dermal or epidermal structures that characteristically form the external covering of fishes, reptiles, and certain mammals.

1. To come off in scales or layers; flake.
2. To become encrusted.
3. To remove tartar from tooth surfaces with a pointed instrument.