river

UK: /ˈrɪvə^r/ US: /ˈrɪvɚ/ ,(riv′ər for 1; rī′vər for 2)

WordReference Random House Learner's Dictionary of American English © 2025

riv•er¹ /ˈrɪvɚ/   n. [countable]

1. a natural stream of water flowing in a definite course:
   Three rivers come together at that city.
   [the + place name + ~]
   the Hudson River.
2. a similar stream of something else:
   rivers of tears.

Idioms

3. Idioms sell (someone) down the river, [Slang.] to betray:
   When he was arrested he realized his so-called friends had sold him down the river.
4. Idioms up the river, [Slang.] to or in prison:
   He was sent up the river for ten years.

WordReference Random House Unabridged Dictionary of American English © 2025

riv•er¹  (riv′ər), n. 

1. a natural stream of water of fairly large size flowing in a definite course or channel or series of diverging and converging channels.
2. a similar stream of something other than water:
   a river of lava; a river of ice.
3. any abundant stream or copious flow;
   outpouring:
   rivers of tears; rivers of words.
4. Astronomy (cap.) the constellation Eridanus.
5. Printing a vertical channel of white space resulting from the alignment in several lines of spaces between words.
6. sell down the river, to betray;
   desert;
   mislead:
   to sell one's friends down the river.
7. up the river, [Slang.]
   • to prison:
     to be sent up the river for a bank robbery.
   • in prison:
     Thirty years up the river had made him a stranger to society.

• Vulgar Latin *rīpāria, noun, nominal use of feminine of Latin rīpārius riparian
• Old French rivere, riviere
• Middle English 1250–1300

riv′er•less, adj. 
riv′er•like′, adj. 

riv•er²  (rī′vər), n. 

1. a person who rives.

• rive + -er¹ 1475–85

Collins Concise English Dictionary © HarperCollins Publishers::

river / ˈrɪvə/ noun

1. a large natural stream of fresh water flowing along a definite course, usually into the sea, being fed by tributary streams
2. (as modifier): river traffic, a river basin
3. (in combination): riverside, riverbed
   Related adjective(s): fluvial, potamic
4. any abundant stream or flow: a river of blood
5. the river ⇒ the fifth and final community card to be dealt in a round of Texas hold 'em

Etymology: 13th Century: from Old French riviere, from Latin rīpārius of a river bank, from rīpa bank

ˈriverless adjective