I was amazed to find "The Undertones" still painted on a wall by the canal in Falkirk. It must have been there nearly 40 years. In Physics, we have overtones. This applies to the stationary waves produced by instruments. The longest stationary wave to fit into an instrument is called the FUNDAMENTAL MODE. It is fixed by the boundary conditions: for a guitar string that means a fixed point or node at each end. The higher frequencies that also fit in are called OVERTONES.
