by Colin McIntosh, The Cambridge English Dictionary is constantly being updated and expanded to reflect the interests of our users. One area of particular interest to our users is that of English Language Teaching (ELT), and a number of ELT terms have recently been added to the dictionary.y Colin McIntosh, The Cambridge English Dictionary is constantly being updated and expanded to reflect the interests of our users. One area of particular interest to our users is that of English Language Teaching (ELT), and a number of ELT terms have recently been added to the dictionary.
A diode is a one-way âvalveâ for electric current, analogous to a check valve for those familiar with plumbing and hydraulic systems. Ideally, a diode provides unimpeded flow for current in one direction (little or no resistance), but prevents flow in the other direction (infinite resistance).
Rivers can flow down mountains, through valleys (depressions) or along plains, and can create canyons or gorges. The term upriver (or upstream) refers to the direction towards the source of the river, i.e. against the direction of flow. Likewise, the term downriver (or downstream) describes the direction towards the mouth of the river, in which the current flows.