Old English flod "a flowing of water, flood, an overflowing of land by water, Noah's Flood; mass of water, river, sea, wave," from Proto-Germanic *flothuz (cf. Old Frisian flod, Old Norse floð, Middle Dutch vloet, Dutch vloed, German Flut, Gothic flodus), from PIE verbal stem *pleu- "flow, float" (see pluvial). Figurative use by mid-14c.