Online Etymology Dictionary

flood (n.): O.E. flod "a flowing of water, river, sea, flood," from P.Gmc. *flothuz (cf. O.Fris. flod, O.N. floð, M.Du. vloet, Ger. Flut, Goth. fiodus), from PIE verbal stem *plo-/*pleu- "flow, float" (cf. Gk. ploein "to float, swim," plotos "floating, navigable"). The verb is first attested 1660s. Related: Flooded; flooding. Flood plain (also floodplain) is from 1873.
floodgate: early 13c. in the figurative sense (especially with reference to tears or rain); literal sense is mid-15c.; from flood + gate.
freshet: 1596, "stream flowing into the sea," from fresh in a now obsolete sense of "flood, stream of fresh water." Meaning "flood caused by rain or melting snow" is from 1654.
spate: early 15c., originally Scottish and northern English, "a sudden flood, especially one caused by heavy rains or a snowmelt," of unknown origin. Perhaps from O.Fr. espoit "flood," from Du. spuiten "to flow, spout;" related to spout. Figurative sense of "unusual quantity" is attested from 1610s.
antediluvian: "before Noah's flood," 1646, formed from L. ante- "before" (see ante) + diluvium "a flood" (see deluge). Coined by Eng. physician Sir Thomas Browne (1605-1682).
lake (1): "body of water," c.1200, from O.Fr. lack, from L. lacus "pond, lake," also "basin, tank," related to lacuna "hole, pit," from PIE *lak- (cf. Gk. lakkos "pit, tank, pond," O.C.S. loky "pool, puddle, cistern," O.Ir. loch "lake, pond"). The common notion is "basin." There was a Gmc. form of the word, which yielded cognate O.N. lögr "sea flood, water," O.E. lacu "stream," lagu "sea flood, water," leccan "to moisten" (see leak). The N.Amer. Great Lakes so called from 1660s. Laker "boat made for sailing on the Great Lakes" is from 1887.
libation: late 14c., "pouring out of wine in honor of a god," from L. libationem (nom. libatio) "a drink offering," from libare "pour out (an offering)," from PIE *(s)leib- "to pour, drop" (cf. Gk. leibein "to pour, make a libation"), an enlargement of base *lei- "to pour, to flow" (cf. Skt. riyati "to let run;" Gk. aleison "a wine vessel;" Lith. lieju "to pour," lytus "rain;" Hitt. lilai- "to let go;" Alb. lyse, lise "a stream;" Welsh lliant "a stream, a sea," llifo "to flow;" O.Ir. lie "a flood;" Bret. livad "inundation;" Gael. lighe "a flood, overflow;" Goth. leithu "fruit wine;" O.C.S. liti, lêju, Bulg. leja "I pour;" Czech liti, leji, O.Pol. lic' "to pour"). Transf. sense of "liquid poured out to be drunk" is from 1751.
Ogygian: 1843, "of great antiquity or age," from Gk. Ogygos, name of a mythical Attic or Boeotian king who even in classical times was thought to have lived very long ago. Also sometimes with reference to a famous flood said to have occurred in his day.
neap: O.E. nepflod "neap flood," the tide occurring at the end of the first and third quarters of the lunar month, in which high waters are at their lowest, of unknown origin, with no known cognates (Dan. niptid probably is from English). Original sense seems to be "without power."
Noah: masc. proper name, from Heb. Noah, lit. "rest." Noachian, in ref. to the flood legend, is from 1678.
bask: late 14c., basken "to wallow (in blood)," from O.N. baðask, reflexive of baða "bathe" (see bathe). Modern meaning "soak up a flood of warmth" is apparently due to Shakespeare's use of the word in reference to sunshine in "As You Like It" (1600).
gust: 1588, possibly a dial. survival from O.N. gustr "a cold blast of wind," or O.H.G. gussa "flood," both from P.Gmc. *gustiz, from PIE *gheus-, from root *gheu- "to pour." Probably originally in Eng. as a nautical term.
overflow (v.): O.E. oferfleow "to flow across, flood, inundate," also "to flow over (a brim or bank)," from ofer "over" + fleow "flow." The noun is attested from 1589.
suds: 1548, "dregs, leavings, muck," especially in East Anglia, "ooze left by flood" (this may be the original sense), perhaps borrowed from M.Du. sudse "marsh, bog," cognate with O.E. soden, pp. of seoþan (see seethe). Meaning "soapy water" dates from 1581; slang meaning "beer" first attested 1904.
ravage: 1611, from Fr. ravager "lay waste, devastate," from O.Fr. ravage "destruction," especially by flood, 14c., from ravir "to take away hastily" (see ravish).
regurgitation: c.1600, from M.L. regurgitationem, noun of action from regurgitare "to overflow," from L.L. re- "back" + gurgitare "engulf, flood" (found in L. ingurgitare "to pour in"), from gurges "whirlpool, gorge, abyss." Meaning "to vomit" first attested 1753.
shibboleth: 1382, the Heb. word shibboleth "flood, stream," also "ear of corn," in Judges xii:4-6. It was the password used by the Gileadites to distinguish their own men from fleeing Ephraimites, because Ephraimites could not pronounce the -sh- sound. Figurative sense of "watchword" is first recorded 1638, and it evolved by 1862 to "outmoded slogan still adhered to." A similar test-word was cicera "chick pease," used by the Italians to identify the French (who could not pronounce it correctly) during the massacre called the Sicilian Vespers (1282).
debacle: "disaster," 1848, fig. use of Fr. débâcle "breaking up of ice on a river," extended to the violent flood that follows when the river ice melts in spring, from débâcler "to free," from M.Fr. desbacler "to unbar," from des- "off" + bacler "to bar," from V.L. *bacculare, from L. baculum "stick." Sense of "disaster" was present in Fr. before Eng. borrowed the word.
flash: late 14c., from flasken (c.1300) "to dash or splash" (as water), probably imitative. Related: Flashed. Sense of "give off a sudden burst of light or flame" is 1540s, as is the noun. Meaning "photographic lamp" is from 1913. Flash in the pan (1809) is from old-style guns, where the powder might ignite in the pan but fail to spark the main charge. Flash flood is from 1940; flash point (also flashpoint) is from 1878, figurative use by 1955.
lava: 1750, from It. (Neapolitan or Calabrian dialect) lava "torrent, stream," traditionally from L. lavare "to wash" (see lave). Originally applied in It. to flash flood rivulets after downpours, then to streams of molten rock from Vesuvius. Alternative etymology is from L. labes "a fall," from labi "to fall." Lava lamp is attested from 1970, earlier lava light (reg. U.S., 1968, as Lava Lite).
surround: 1423, "to flood, overflow," from M.Fr. soronder "to overflow, abound, surpass, dominate," from L.L. superundare "overflow," from L. super "over" (see super-) + undare "to flow in waves," from unda "wave" (see water; and cf. abound). Sense of "to shut in on all sides" first recorded 1616, influenced by figurative meaning in Fr. of "dominate," and by sound association with round. First record of surroundings in sense of "environment" is from 1861.
folklore: 1846, coined by antiquarian William J. Thoms (1803-1885) as an Anglo-Saxonism (replacing popular antiquaries) and first published in the "Athenaeum" of Aug. 22, 1846, from folk + lore. This word revived folk in a modern sense of "of the common people, whose culture is handed down orally," and opened up a flood of compound formations, eg. folk art (1921), folk-hero (1899), folk-medicine (1898), folk-tale/folk tale (1891), folk-song (1847), folk-dance (1912).
flush (v.): "fly up suddenly," c.1300, perhaps imitative of the sound of beating wings, or related to flash via its variant flushe. Probably not connected to O.Fr. flux, source of flush (n.). Transitive meaning "to cause to fly, start" is first attested mid-15c. The sense of "spurt, rush out suddenly, flow with force" (1540s) is probably the same word, with the connecting notion being "sudden movement," but its senses seem more to fit the older ones of flash (now all transferred to this word except in flash flood). The noun sense of "sudden redness in the face" (1620s) probably belongs here, too. "A very puzzling word" [Weekley]. Related: Flushed flushing.
P: a rare letter in the initial position in Gmc., in part because by Grimm's Law PIE p- became Gmc. f-; even with early L. borrowings, -p- takes up only a little over 4 pages in J.R. Clark Hall's "Concise Anglo-Saxon Dictionary," compared to 31 pages for B and more than 36 for F. But it now is the third most common initial letter in the Eng. vocabulary, and with C and S, comprises nearly a third of the words in the dictionary, a testimonial to the flood of words that have entered the language since 1066 from L., Gk., and Fr. To mind one's Ps and Qs (1779), possibly is from confusion of these letters among children learning to write. Another theory traces it to old-time tavern-keepers tracking their patrons' bar tabs in pints and quarts. But cf. also to be P and Q (1612), "to be excellent," a slang phrase said to derive from prime quality.
tide: O.E. tid "point or portion of time, due time," from P.Gmc. *tidiz "division of time" (cf. O.S. tid, Du. tijd, O.H.G. zit, Ger. Zeit "time"), from PIE *di-ti- "division, division of time," suffixed form of base *da- "to divide, cut up" (cf. Skt. dati "cuts, divides;" Gk. demos "people, land," perhaps lit. "division of society;" daiesthai "to divide;" O.Ir. dam "troop, company"). Meaning "rise and fall of the sea" (1340) is probably via notion of "fixed time," specifically "time of high water;" either a native evolution or from M.L.G. getide (cf. also Du. tij, Ger. Gezeiten "flood tide"). O.E. had no specific word for this, using flod and ebba to refer to the rise and fall. The verb meaning "to carry (as the tide does)" is recorded from 1626, usually with over.
C: third letter of the alphabet. Alphabetic writing came to Rome via the southern Etruscan "Caeretan" script, in which gamma was written as a crescent. Early Romans made little use of Gk. kappa and used gamma for both the "g" and "k" sounds, the latter more frequently, so that the "k" sound came to be seen as the proper one for gamma. To restore a dedicated symbol for the "g" sound, a modified gamma was introduced c.250 B.C.E. as G. In classical Latin -c- has only the value "k," and thus it passed to Celtic and, via Irish monks, to Anglo-Saxon, where -k- was known but little used. In O.Fr., many "k" sounds drifted to "ts" and by 13c., "s," but still were written with a -c-. Thus the 1066 invasion brought to the Eng. language a more vigorous use of -k- and a flood of Fr. and L. words in which -c- represented "s" (e.g. cease, ceiling, circle). By 15c. native English words with -s- were being respelled with -c- for "s" (e.g. ice, mice, lice). In some words from Italian, meanwhile, the -c- has a "ch" sound (a sound evolution in Italian that parallels the O.Fr. one).