Purfling is a narrow decorative edge inlaid into the top plate and often the back plate of a stringed instrument. Wikipedia

A narrow decorative wooden strip inlaid into the top and bottom plates of stringed instruments Wikipedia Disambiguation

Narrow decorative wooden strip inlaid into the top and bottom plates of stringed instruments Wikidata

Two or more very narrow strips of black wood enclosing a lighter-coloured strip of wood set close to the edge of the top and back of a string instrument such as a violin, cello or a guitar, following its outline, or this effect simulated with paint. Wiktionary