Source (headwaters)The point where a river begins. It can be a spring, melting ice or a marsh. The small streams of the upper reaches, taken together, are called the headwaters.
TributaryA smaller river or stream that flows into a larger one. Several small tributaries usually merge to form a river. A tributary brings water in, and a distributary carries it away.
ConfluenceWhere two or more streams join into one channel. The larger one is the main stem, or trunk river. The Ohio River begins at a confluence, where the Allegheny and the Monongahela meet at Pittsburgh.
ChannelThe passage the river flows in. That means its bed and the sides that hold the water. The line of deepest water along it is called the thalweg.
Bank (riverbank)The land alongside the river, forming the sides of the channel. Left bank and right bank are named as seen by someone facing downstream, the way the water flows.
MeanderOne of a series of winding curves in a river's course. The word comes from the Menderes, a winding river in what is now Turkey that the ancient Greeks called Maiandros.
Oxbow lakeA U-shaped lake that was once a meander. The river wore through the narrow neck of the loop and took the shorter path, and sediment then sealed off the old loop. In Australia it is called a billabong.
FloodplainThe relatively flat, normally dry land beside a river. Water covers it during a flood. Each flood spreads a layer of stream-deposited sediment, called alluvium, across it.
DeltaLow, nearly flat land built at the end of a river. It forms from sediment that tides, waves and currents do not carry away. The name comes from the Nile Delta, whose triangle looks like the Greek capital letter delta.
MouthWhere a river meets a larger body of water. This is a sea, an ocean, a lake or another river. The current slows here and drops its sediment, which can build a delta.
Upper course 3
V-shaped valleyHigh in its course a river cuts mostly downward into its bed. That leaves a steep-sided valley shaped like a V. A valley carved by a glacier is U-shaped.
WaterfallWater falls over a vertical drop. Often hard rock lies over softer rock there. The falling water scours a plunge pool at the bottom, and over time the fall wears back upstream and leaves a gorge.
RapidsA stretch where the riverbed is steep. So the water speeds up and turns rough. It runs shallow over exposed rocks, and air mixed into the water turns it white, which is where the word whitewater comes from.
Middle course 3
Riparian zoneThe strip where land meets a river or stream. It is named from the Latin ripa, river bank. Its plants help hold the banks together, filter runoff before it reaches the water, and shade the stream.
Cut bank (river cliff)The steep, bare slope on the outside of a bend. The current wears this side away and undercuts it, so the bend slowly moves outward across the plain.
Point bar (slip-off slope)A low ridge of sand and gravel. It is laid down on the inside of a bend, where the water slows. It grows while the opposite side is worn away, which is how a bend travels across the floodplain.
Lower course 2
Natural leveeA long, low ridge of sand and coarse silt. Floodwater spilling over builds it up along both sides of the channel. The same word is used for an earthen barrier that people build along a river.
DistributaryA channel that branches off the main river and flows away. A tributary's opposite. Distributaries are common on deltas, where a river can split again and again.
How this list was compiled: Part names and every detail line were checked, for facts only and with nothing copied, against these pages, all read 2026-09-19. U.S. Geological Survey, Water Science School: Water Science Glossary, https://www.usgs.gov/special-topics/water-science-school/science/water-science-glossary (headwaters, tributary, flood plain, levee, estuary, watershed and drainage basin, river); and Rivers, Streams, and Creeks, https://www.usgs.gov/special-topics/water-science-school/science/rivers-streams-and-creeks (small creeks merging into rivers, nearly all rivers ending in the oceans). U.S. National Park Service: Fluvial Landforms, https://www.nps.gov/subjects/geology/fluvial-landforms.htm (floodplain, natural levees, a trunk river and its tributaries, upper, middle and lower basin); and the Geologic Resources Inventory glossary, https://www.nps.gov/subjects/geology/gri-glossary-of-geologic-terms.htm, read from its data file https://www.nps.gov/common/uploads/sortable_dataset/geology/DBD85DC6-CA83-CEE3-0786454132D79FCD/nri-GlossaryTable.csv (meander, point bar, cutbank, oxbow, delta, levee, floodplain, channel, thalweg, alluvium, estuary). Terms those two agencies do not define were checked on Wikipedia: https://en.wikipedia.org/wiki/River_source (spring, meltwater and marsh sources), https://en.wikipedia.org/wiki/Valley (V-shaped river valleys, U-shaped glacial valleys, upper, middle and lower valley), https://en.wikipedia.org/wiki/Waterfall (hard rock over soft, plunge pool, retreat upstream, gorge), https://en.wikipedia.org/wiki/Rapids (steep bed, shallow water, exposed rocks, whitewater), https://en.wikipedia.org/wiki/Confluence (definition, main stem, the Ohio at Pittsburgh), https://en.wikipedia.org/wiki/Bank_(geography) (bank as the sides of the channel, left and right bank facing downstream), https://en.wikipedia.org/wiki/Riparian_zone (definition, Latin ripa, bank stability, filtering, shade), https://en.wikipedia.org/wiki/Meander (outer cut bank or river cliff, inner point bar, slip-off slope, the Menderes, thalweg), https://en.wikipedia.org/wiki/Oxbow_lake (cutoff through the meander neck, sealing by deposition, billabong), https://en.wikipedia.org/wiki/Distributary (definition, opposite of a tributary, common on deltas), https://en.wikipedia.org/wiki/River_delta (why sediment drops, the Nile and the Greek letter, estuaries on coasts with a large tidal range) and https://en.wikipedia.org/wiki/River_mouth (definition, slowing current, sediment). Licence: own work
The drawing: Drawn for this site, 2026-09-20. An invented river, not a map of a real one; nothing was traced or copied. Looked at for accuracy (text only): the Wikipedia articles Meander, Oxbow lake, River delta, Levee, Cut bank, Waterfall and Riparian zone. Licence: own work
How it works
This drawing follows one river from a spring in the mountains to a delta on the coast. Eighteen parts carry a numbered ring in the order the water meets them. Number 1 is the source and number 18 is the mouth. Choose Find it to tap each named part, or Name it to name the ring that lights. Miss two, and Practise the 2 you missed asks again.
Read the full guide
Label a river from source to mouth
Find it gives a name, say confluence, and you tap its ring. A miss shows the right ring. In Name it, pick from four names or press Type it, where riverbank counts for bank and billabong for oxbow lake. The Upper course set holds 6 parts, from the source down to the confluence. Middle course has the 7 around the big bends. Lower course has the 5 on the plain and at the coast.
The parts of a river system, and a blank to print
The river system set keeps the 6 parts of a river system that form the network itself: where water starts, joins, splits and ends. Erosion and deposition holds the 8 landforms the river cuts or builds. Print blank gives a class the river with 18 numbered rings and 18 empty lines, and Print labelled is the key.
A tributary contributes water to the river. A distributary distributes it, carrying water away across the delta.
On any bend, think fast outside, slow inside. Fast water carves the cut bank, and slow water drops sand on the point bar.
Left bank and right bank are named facing downstream. This river flows toward you, so its left bank is on your right.
Questions and answers
What are the main parts of a river?
Start with ten: source, tributary, confluence, channel, bank, meander, oxbow lake, floodplain, delta and mouth. The Simple: 10 main parts set asks only these. The other 8 go further: V-shaped valley, waterfall, rapids, riparian zone, cut bank, point bar, natural levee and distributary.
How does an oxbow lake form?
A meander grows because its outer side wears away while sand builds up inside the bend. When only a narrow neck of land is left, the river wears through it and takes the shorter path. Sediment seals off the old loop, and the curved, still water left behind is the oxbow lake.
Why is there no estuary or watershed on this drawing?
A river ends in a delta or in an estuary, the tidal mouth where fresh water and seawater mix. One drawing can show only one. The watershed, or drainage basin, is all the land that drains to a river, which is too wide for this drawing.