span·ner 
(spănər)
(spănər)n.
1. A wrench having a hook, hole, or pin at the end for meshing with a related device on another object.
2. Chiefly British A wrench.
[German, winding tool, from spannen, to stretch, from Middle High German, from Old High German spannan; see (s)pen- in the Appendix of Indo-European roots.]