river bed (river beds plural) , riverbed A river bed is the ground which a river flows over. n-count. up-river, upriver. Something that is moving up-river is moving towards the source of a river, from a point down the river.
In economics, the term trade-off is often expressed as an opportunity cost, which is the most preferred possible alternative. A trade-off involves a sacrifice that must be made to get a certain product or experience. A person gives up the opportunity to buy 'good B,' because they want to buy 'good A' instead.
Trade refers to buying and selling of goods and services for money or money's worth. It involves transfer or exchange of goods and services for money or money's worth. The manufacturers or producer produces the goods, then moves on to the wholesaler, then to retailer and finally to the ultimate consumer.