early 13c. (late 12c. in surnames), "a considerable body of water flowing with perceptible current in a definite course or channel," from Anglo-French rivere, Old French riviere "river, riverside, river bank" (12c.), from Vulgar Latin *riparia "riverbank, seashore, river" (source also of Spanish ribera, Italian riviera), noun use of fem. of Latin riparius "of a riverbank" (see riparian).

The generalized sense of "a copious flow" of anything is from late 14c., as is figurative use. The Old English word was ea "river," cognate with Gothic ahwa, Latin aqua (see aqua-). Romanic cognate words tend to retain the sense "river bank" as the main one, or else the secondary Latin sense "coast of the sea" (compare Riviera). In printing by 1898: "streaks of white space in text caused by the spaces between words in several lines happening to fall one almost below the other."

U.S. slang phrase up the river "in prison" (1891) is said to be originally in reference to Sing Sing prison, up the Hudson River from New York City. The phrase down the river "done for, finished" (1893) perhaps echoes the sense in sell down the river (1836, American English), originally of slaves sold from the Upper South to the harsher plantations of the Deep South.

river through London, Old English Temese, from Latin Tamesis (51 B.C.E.), from British Tamesa, an ancient Celtic river name perhaps meaning "the dark one." The -h- is unetymological (see th).

"a tidal river," 1650s; see salt (n. ) + river. as a proper name, it was used early 19c. with reference to backwoods inhabitants of the U.S., especially those of Kentucky (there is a Salt River in the Bluegrass region of the state; the river is not salty, but salt manufactured from salt licks in the area was shipped down the river). The U.S. political slang phrase to row (someone) up Salt River "send (someone) to political defeat" probably owes its origin to this geographical reference, as the first attested use (1828) is in a Kentucky context. The phrase may also refer to the salt of tears.

1773, from up + river. As an adverb from 1848.

"sloping edge or border of a river," 1560s, from river (n.) + bank (n.2).

"alluvial land along the margin of a river," 1752, American English, from river (n.) + bottom (n.).

collar (1882), jacket (1873, formerly worn by the younger boys there), etc., from Eton College, public school for boys on the Thames opposite Windsor, founded by Henry VI. The place name is Old English ea "river" (see ea) + tun "farm, settlement" (see town (n.)). Related: Etonian.

1670s, coarse, abusive language of the sort once used by women in the Billingsgate market on the River Thames below London Bridge.

Billingsgate is the market where the fishwomen assemble to purchase fish; and where, in their dealings and disputes they are somewhat apt to leave decency and good manners a little on the left hand. [Grose, "A Classical Dictionary of the Vulgar Tongue," 1788]

The place name is Old English Billingesgate, "gate of (a man called) Billing;" the "gate" probably being a gap in the Roman river wall. The market there is from mid-13c.; it was not exclusively a fish market until late 17c.

1844, in a London context in reference to the area south of the Thames, from Latin trans "across, beyond" (see trans-) + pontine, from stem of pons "bridge" (see pons).

town on the Thames in Oxfordshire, site of annual regatta since 1839. The name is Old English hean-leage "(settlement) at or by the high wood."