throng: [13] The etymological notion underlying throng is of ‘pressing together’. It was borrowed from Old Norse throng ‘crowd’, which went back ultimately to the prehistoric Germanic base *thringg- ‘press’ (source also of German drang ‘crowd, pressure’ and dringen ‘press’). Amongst its non-Germanic relatives is Old Persian thraxta- ‘closely-packed’.
throng (n.)
c. 1300, probably shortened from Old English geþrang "crowd, tumult" (related to verb þringan "to push, crowd, press"), from Proto-Germanic *thrangan (cognates: Old Norse þröng, Dutch drang, German Drang "crowd, throng").
throng (v.)
"go in a crowd," 1530s, from throng (n.). Earlier it meant "to press, crush" (c. 1400). Related: Thronged; thronging.