An Etymological Dictionary of the German Language/Annotated/strack

by Friedrich Kluge

strack, adjective, ‘extended, direct, tense,’ from Middle High German strac (ck), ‘straight, tight,’ to which Modern High German stracks, adverb, ‘straightway, immediately,’ from Middle High German strackes, is allied; so too Modern High German strecken, ‘to stretch, extend.’