c. 1300, probably shortened from Old English geþrang "crowd, tumult" (related to verb þringan "to push, crowd, press"), from Proto-Germanic *thrangan (source also of 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.
thrombo-
thrombophlebitis
thrombosis
thrombus
throne
throng
throstle
throttle
through
throughly
throughout