The path where a river runs, or where a river once ran; the bottom earthen part of a river, not including the riverbanks.
From river + bed. Compare Dutch rivierbedding (“riverbed”), German Flussbett (“riverbed”), Swedish flodbädd (“riverbed”).
Ćwicz mówienie i zapamiętywanie " riverbed " i wielu innych słów i zdań z angielski .