D defs.my
Entry 4 senses Webster, 1913

spanner

/(spăn"nẽr)/ · span·ner · IPA /ˈspæn.ə/
01 n. One who, or that which, spans.
  1. 1.
    One who, or that which, spans.
  2. 2.
    The lock of a fusee or carbine; also, the fusee or carbine itself.[Obs.]
  3. 3.
    An iron instrument having a jaw to fit a nut or the head of a bolt, and used as a lever to turn it with; a wrench; specifically, a wrench for unscrewing or tightening the couplings of hose.[Chiefly British usage]
  4. 4.
    A contrivance in some of the earlier steam engines for moving the valves for the alternate admission and shutting off of the steam.