MEANDER A meander in general is a bend in a sinuous watercourse. A meander is formed when the moving water in a stream erodes the outer banks and widens its valley.

FALLLINE A fall line (or fall zone) is a geomorphologic unconformity (e.g., monoclinal faulting and/or flexing)[1] between an upland region of relatively hard crystalline basement rock and a coastal plain of softer sedimentary rock A fall line is typically prominent when crossed by a river, for there will often be rapids or waterfalls.

CANYON A canyon (occasionally spelled cañon) or gorge is a deep ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into.

BASIN Drainage basin (hydrology), a topographic region in which all water drains to a common area

ABYSSAL PLAIN An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 meters. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth’s surface.

WATERSHED A watershed is the area of land where all of the water that is under it or drains off of it goes into the same place.

DELTA A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river.

FAULT LINE A fault line is the surface trace of a fault, the line of intersection between the fault plane and the Earth's surface. Since faults do not usually consist of a single, clean fracture, geologists use the term fault zone.

MOUNTAIN A mountain is a large landform that stretches above the surrounding land in a limited area usually in the form of a peak. A mountain is generally steeper than a hill. The adjective montane is used to describe mountainous areas and things associated with them. The study of mountains is called Orography.

FLOODPLAIN A floodplain, or flood plain, is a flat or nearly flat land adjacent to a stream or river that stretches from the banks of its channel to the base of the enclosing valley walls and experiences flooding during periods of high discharge.

TRIBUTARIES A tributary or affluent[1] is a stream or river which flows into a main stem (or parent) river or a lake. [2] A tributary does not flow directly into a sea or ocean. Tributaries and the mainstem river serve to drain the surrounding drainage basin of its surface water and groundwater by leading the water out into an ocean or sea.

VALLEY In geology, a valley or dale is a depression with predominant extent in one direction. A very deep river valley may be called a canyon or gorge. A valley formed by flowing water, or river valley, is usually V-shaped. The exact shape will depend on the characteristics of the stream flowing through it.