Z

Zero Level
This is a standard reference audio level used when discussing relative levels. Commonly the zero level is chosen to be 1 mW. This corresponds to 0.775 volts rms across a 600 Ohm resistance.

Zither
Musical instrument composed of strings mounted upon a resonate frame, strings can be plucked with fingers or struck using small mallets.

If you don't know the blues... there's no point in picking up the guitar and playing rock and roll or any other form of popular music.”
  Keith Richards