Overspun [overwound, wirewound] string.

String with a core of gut or metal that is wound round along its length with a coil or coils of a (relatively thin) ductile wire to increase its mass without substantially increasing stiffness. In non-keyboard string instruments gut cores are generally overspun with aluminium or silver. The steel core bass strings of the modern piano are completely covered with copper, but in some early pianos, spaced brass windings on a brass core string were used. (See String.)

FRANK HUBBARD/DENZIL WRAIGHT