serration

Serration is a pattern of small teeth or notches along a line or edge, producing a sawlike profile. The term derives from the Latin word serra, meaning saw. Serrations occur on natural surfaces and manufactured edges, and can be found in tools, blades, and some biological structures.

In blades and utensils, serration refers to a series of teeth formed along part or all of the cutting edge. Common configurations include large triangular teeth on bread knives and finer serrations on utility or kitchen knives. Some blades combine a serrated section with a straight edge, a setup known as a partially serrated knife. Variants include micro-serrations, scalloped edges, and hollow-ground serrations.

The main function of serrations is to concentrate cutting forces on a series of points rather than along a continuous edge. This design helps the blade slice through fibrous or hard materials, reduces tearing, and can permit starting cuts more easily. Serrated edges tend to retain cutting performance longer as they dull, but they are generally harder to sharpen and may require specialized tools or professional servicing.

Maintenance and sharpening of serrated edges differ from straight-edged blades. Each tooth is typically targeted individually with a tapered rod or a specialized sharpener to maintain the tooth geometry, rather than attempting to re-sharpen the entire edge at once.

Beyond blades, serration appears in biology and engineering. Some predator teeth are serrated to help shear flesh, while in mechanical contexts tooth patterns are used to improve grip, texture, or interlocking action.