What's the difference between these terms in English terminology?
Most Helpful Girl
Generally, the difference is size - You can step over a Brook, jump over a Stream, wade across a Creek, and swim across a River... however, there is no International Standards Committee to dictate even the absolute ranking order of the various terms available for watercourses, so the terminology varies from country to country.
According to The Geographic Names Information System database, the official repository of U. S. geographic names, actually classifies all "linear flowing bodies of water" as Streams (including Bourne, Burn, Creek and Brook).
Bayou is usually marshy or sluggish bodies of water, a moving swamp.
Rivulet is most likely a diminutive for any small river... with permanent flow.1
Most Helpful Guy
River is the largest flowing body of water, it's usually freshwater, flowing towards an ocean, sea, lake or another river.
Rivulet is a small river.
Stream is a general term used for various smaller bodies of water, with a current, confined within a bed and stream bank. Creek, Bourne, Burn, and Brook are just different types of Stream.
Bayou is an American term used for body of water typically found in a flat, low-lying area, and can refer either to an extremely slow-moving stream (with a poorly defined shoreline), or to a marshy lake, or even just a wetland.2