to flow: to stream or gush out, said of any liquid pouring forth
The picture behind this word is liquid in motion: something pours out, runs, or gushes rather than sitting still. The Bible uses it for water bursting from a rock, for a land so fertile it seems to ooze with good things, and for fluid leaking from a body. In every case the same image is at work, only the source changes.
Its most famous use is the promise of a land flowing with milk and honey. The word does not mean the land literally drips; it pictures abundance that streams out without effort, the way a spring keeps running on its own. That is why translators keep the vivid word flowing rather than flattening it to a plain word like rich or fertile.
The same verb turns sober in the law of bodily fluids, where a person who flows is someone with an abnormal discharge that makes them ceremonially unclean. Here the flowing is unwelcome, a leak that has to be dealt with. One stretching use, the people who pine away in Lamentations, lets the flowing run inward: life itself draining out of them. A few scholars suspect that last sense is a separate look-alike word rather than the same one.