Old English flowan "to flow, stream, issue; become liquid, melt; abound, overflow" (class VII strong verb; past tense fleow, past participle flowen), from Proto-Germanic *flo- (cf. Middle Dutch vloyen, Dutch vloeien "to flow," Old Norse floa "to deluge," Old High German flouwen "to rinse, wash"), probably from PIE *pleu- "flow, float" (see pluvial). The weak form predominated from 14c., but strong past participle flown is occasionally attested through 18c. Related: Flowed; flowing.