Reeding

Reeding is a technique wherein "reeds" are carved or milled into a surface.

In numismatics, reeded edges are often referred to as "ridged" or "grooved" (US usage), or "milled" (UK usage). Some coins, such as United States quarters and dimes, 1 euro, Australian 5, 10, 20 cents, 1 and 2 dollars, as well many other current coins, have reeded edges. One reason for having reeded edges was to prevent counterfeiting. Another benefit of certain coins having reeded edges is that it helps enable different coin denominations to be easily identified and distinguished from each other by sense of touch alone.