strack
Origin uncertain. Perhaps a variant of strick, or from Old English stræc (“strict”).
strack (comparative mair strack, superlative maist strack)
From Middle High German strac (“straight”), from Old High German *strak, from Proto-Germanic *strakaz, *strakkaz (“straight”), from Proto-Indo-European *streg-, *treg- (“stiff, rigid”). More at stretch.