piano wire

Hello! Me and some of my classmates are working on designing and building an rc aircraft from scratch, for a project. My job, currently, is to design the landing gear for the aircraft. Due to constraints given to us and a required payload, our final design is roughly 6 lbs when fully loaded...

Flite Test, for some of their scratch builds, say that they were using "music wire" or "piano wire". What exactly is that and why is it called that?