Zweck.

From Middle High German zwec, zwic (“nail, pin made of wood or iron”), from Old High German zwec, zwecki (“nail, peg”), from a root probably related to Zweig (“branch, twig”); this is supported by Kroonen, though Pfeifer is skeptical and leaves the origin open. Compare Swedish svicka, svick, svicke, Danish svik, suicke, Norwegian svikk, all borrowed from Middle Low German swick, in turn borrowed from High German, like Dutch zwik. Originally, Zweck had the meaning “(wooden or iron) nail, peg”, whence “central point of a target” (marked by a nail), whence “target, goal, objective, direction”, whence “intention, function, purpose”.