[English Etymology] *strenk- "tight, narrow, pull tight, twist"

*strenk- "tight, narrow, pull tight, twist"


Eng stretch
   Old English streccan "to stretch, spread out, prostrate; reach, extend" 
        Proto-Germanic *strakjanan


Eng string
   Old English streng "line, cord, thread, string of a bow or harp, ligaments, tendons; lineage, race"
         Proto-Germanic *strangiz 
                                             *strang- "taut, stiff"


Eng strong
    Old English strang "physically powerful, powerful in effect; forceful, severe, firm, bold, brave; constant, resolute; arduous, violent" 
         Proto-Germanic *strangaz