Noun
universal instrument (plural universal instruments)
(astronomy) A kind of altitude and azimuth instrument. The object end of the telescope is placed at right angles to the eye end, with a prism of total reflection at the angle, and the eye end constitutes a portion of the horizontal axis of the instrument, having the eyepiece at the pivot and in the center of the altitude circle, so that the eye has convenient access to both at the same time.
The piano is a universal instrument. If you start there, learn your theory and how to read, you can go on to any other instrument. Eddie Van Halen