scale1

noun

• 1each of the small, thin horny or bony plates protecting the skin of fish and reptiles, typically overlapping one another.

• 2something resembling a fish scale in appearance or function, in particular:
• a thick dry flake of skin.
• a rudimentary leaf, feather, or bract.
• each of numerous microscopic tile-like structures covering the wings of butterflies and moths.

• 3 [mass noun] a flaky deposit, in particular:
• a white deposit formed in a kettle, boiler, etc. by the evaporation of water containing lime: banging sounds emanating from the boiler may be caused by a build-up of scale
• tartar formed on teeth.
• a coating of oxide formed on heated metal: a spray-on chemical for removing welding scale and heat discoloration from stainless steel

verb

• 1 [with object] remove scale or scales from:he scales the fish and removes the innards
• remove tartar from (teeth) by scraping them: dental hygienists give treatment such as scaling and polishing teeth

• 2 [no object] (often as noun scaling) (especially of the skin) form scales:moisturizers can ease off drying and scaling
• come off in scales or thin pieces; flake off:the paint was scaling from the brick walls