1550s, "action of putting in tune," verbal noun from tune (v.). Of motors, from 1863. Tuning fork attested from 1776, supposedly invented by John Shore (d.1753), royal trumpeter.
[Shore] was a man of humour and pleasantry, and was the original inventor of the tuning-fork, an instrument which he constantly carried about him, and used to tune his lute by, and which whenever he produced it gave occasion to a pun. At a concert he would say, "I have not about me a pitch-pipe, but I have what will do as well to tune by, a pitch-fork." [Sir John Hawkins, "A General History of the Science and Practice of Music," London, 1776]