flock (n.2) Look up flock at Dictionary.com
"tuft of wool," mid-13c., probably from Old French floc, from Latin floccus "flock of wool, lock of hair."
flock (v.) Look up flock at Dictionary.com
"gather, congregate," c.1300, from flock (n.). Related: Flocked; flocking.
floe (n.) Look up floe at Dictionary.com
1817, first used by Arctic explorers, probably from Norwegian flo "layer, slab," from Old Norse flo, related to first element in flagstone (q.v.). Earlier explorers used flake.
flog (v.) Look up flog at Dictionary.com
1670s, slang, perhaps a schoolboy shortening of Latin flagellare "flagellate." Related: Flogged; flogging.
flood (n.) Look up flood at Dictionary.com
Old English flod "a flowing of water, flood, an overflowing of land by water, Noah's Flood; mass of water, river, sea, wave," from Proto-Germanic *floduz "flowing water, deluge" (cognates: Old Frisian flod, Old Norse floð, Middle Dutch vloet, Dutch vloed, German Flut, Gothic flodus), from PIE verbal stem *pleu- "flow, float" (see pluvial). Figurative use by mid-14c.
flood (v.) Look up flood at Dictionary.com
1660s, from flood (n.). Related: Flooded; flooding.
floodgate (n.) Look up floodgate at Dictionary.com
early 13c. in the figurative sense (especially with reference to tears or rain); literal sense is mid-15c.; from flood (n.) + gate (n.).
floodplain (n.) Look up floodplain at Dictionary.com
also flood plain, 1873, from flood (n.) + plain (n.).
floor (v.) Look up floor at Dictionary.com
early 15c., "to furnish with a floor," from floor (n.). Sense of "puzzle, confound" is 1830, from notion of "knock down to the floor" (1640s). Related: Floored; flooring.
floor (n.) Look up floor at Dictionary.com
Old English flor "floor, pavement, ground, bottom (of a lake, etc.)," from Proto-Germanic *floruz "floor" (cognates: Middle Dutch and Dutch vloer, Old Norse flor "floor," Middle High German vluor, German Flur "field, meadow"), from PIE *plaros "flat surface" (source also of Welsh llawr "ground"), enlarged from *pele- (2) "flat, to spread" (see plane (n.1)).

Meaning "level of a house" is from 1580s. The figurative sense in legislative assemblies (as opposed to the platform) is first recorded 1774. Spanish suelo "floor" is from Latin solum "bottom, ground, soil;" German Boden is cognate with English bottom. Floor plan attested from 1867.
flooring (n.) Look up flooring at Dictionary.com
"materials of a floor," 1620s, verbal noun from floor (v.).
floozie (n.) Look up floozie at Dictionary.com
also floozy, "woman of disreputable character," 1902, perhaps a variation of flossy "fancy, frilly" (1890s slang), with the notion of "fluffiness."
flop (v.) Look up flop at Dictionary.com
c.1600, probably a variant of flap with a duller, heavier sound. Sense of "fall or drop heavily" is 1836, that of "collapse, fail" is 1919; though the figurative noun sense of "a failure" is recorded from 1893. Related: Flopped; flopping.
flop (n.) Look up flop at Dictionary.com
1823, in the literal sense, from flop (v.). Figurative use by 1893.
flophouse (n.) Look up flophouse at Dictionary.com
"cheap hotel," hobo slang, 1904, probably related to slang flop (v.) "lie down for sleep" (1907); see flop (v.) + house (n.).
In one of [Cincinnati's] slum districts stands the Silver Moon, a "flop house" (i.e., a house where the occupants are "flopped" out of their hanging bunks by letting down the ropes) .... ["McClure's" magazine, November 1904]
(But this explanation is not found in other early references.)
floppy (adj.) Look up floppy at Dictionary.com
1858, from flop + -y (2). Floppy disc attested from 1972 (short form floppy by 1974).
flora (n.) Look up flora at Dictionary.com
1777, "the plant life of a region or epoch," from Latin Flora, Roman goddess of flowers, from flos (genitive floris) "flower," from *flo-s-, Italic suffixed form of PIE *bhle- "to blossom, flourish" (cognates: Middle Irish blath, Welsh blawd "blossom, flower," Old English blowan "to flower, bloom"), extended form of *bhel- (3) "to thrive, bloom," possibly identical with *bhel- (2) "to blow, swell" (see bole). Used as the title of descriptive plant catalogues since 1640s, but popularized by Linnaeus in his 1745 study of Swedish plants, "Flora Suecica."
floral (adj.) Look up floral at Dictionary.com
1640s, "pertaining to Flora," from French floral (16c.), from Latin floralis "of flowers" (see flora). Meaning "pertaining to flowers" is from 1753.
Florence Look up Florence at Dictionary.com
fem. proper name, from Latin Florentia, fem. of Florentius, literally "blooming," from florens (genitive florentis), present participle of florere "to flower" (see flourish). The c.1700 "Dictionary of the Canting Crew" defines Florence as a slang word for "a Wench that is touz'd and ruffled." This was also the Italian city name (Roman Colonia Florentia, "flowering colony," either literal or figurative), which became Old Italian Fiorenze, in modern Italian Firenze.
Florentine (adj.) Look up Florentine at Dictionary.com
1540s, literally "of or pertaining to the Italian city of Florence," from Latin Florentinus, from Florentia (see Florence). Earliest reference in English is to a type of textile fabric.
florescence (n.) Look up florescence at Dictionary.com
1793, from Modern Latin florescentia, from Latin florescentem (nominative florescens) "blooming," present participle of florescere "to begin to bloom," inceptive of florere "to blossom" (see flourish (v.)).
florescent (adj.) Look up florescent at Dictionary.com
1821, from Latin florescentem, present participle of florescere (see florescence).
floret (n.) Look up floret at Dictionary.com
c.1400, flourette, from Old French florete "little flower; cheap silk material," diminutive of flor "flower," from Latin flora (see flora). Botany sense is from 1670s.
floricide (n.) Look up floricide at Dictionary.com
"one who destroys flowers," 1841, from Latin floris, genitive of flos "flower" (see flora) + -cide.
floriculture (n.) Look up floriculture at Dictionary.com
1822, from Latin floris, genitive of flos "flower" (see flora) + -culture on analogy of agriculture. Related: Floricultural; floriculturist.
florid (adj.) Look up florid at Dictionary.com
1640s, "strikingly beautiful," from French floride "flourishing," from Latin floridus "flowery, in bloom," from flos "flower" (see flora). Sense of "ruddy" is first recorded 1640s. Meaning "profusely adorned, as with flowers," is from 1650s. Related: Floridly.
Florida Look up Florida at Dictionary.com
U.S. state, formerly a Spanish colony, probably from Spanish Pascua florida, literally "flowering Easter," a Spanish name for Palm Sunday, because the peninsula was discovered on that day (March 20, 1513) by the expedition of Spanish explorer Ponce de León (1474-1521). From Latin floridus (see florid).
florin (n.) Look up florin at Dictionary.com
c.1300, from Old French florin, from Italian fiorino, from fiore "flower," from Latin florem "flower" (see flora). The 13c. gold Florentine coin was stamped on the obverse with the image of a lily, the symbol of the city. As the name of an English gold coin, from late 15c.
florist (n.) Look up florist at Dictionary.com
1620s, formed on analogy of French fleuriste, from Latin floris, genitive of flos "flower" (see flora) + -ist.
floruit Look up floruit at Dictionary.com
used now mainly in sense of "period during which a historical person's life work was done," 1843, Latin, literally "he flourished," third person singular perf. indicative of florere (see flourish (v.)). Usually in abbreviation fl.
floss (n.) Look up floss at Dictionary.com
"rough silk," 1759, perhaps from French floche "tuft of wool" (16c.), from Old French floc "tuft, lock," from Latin floccus "tuft of wool." Or from an unrecorded Old English or Old Norse word from the root found in Dutch flos "plush" (17c.). Compare the surname Flossmonger, attested 1314, which might represent a direct borrowing from Scandinavian or Low German. In "The Mill on the Floss" the word is the proper name of a fictitious river in the English Midlands.
flossy (adj.) Look up flossy at Dictionary.com
"resembling floss," 1839, from floss + -y (2).
flotation (n.) Look up flotation at Dictionary.com
1850s, from float (v.) + -ation. Spelling influenced by French (compare floatation).
flotilla (n.) Look up flotilla at Dictionary.com
1711, "a small fleet," from Spanish flotilla, diminutive of flota "float," from flotar "to float," of Germanic origin (see float (v.)).
flotsam (n.) Look up flotsam at Dictionary.com
c.1600, from Anglo-French floteson, from Old French flotaison "a floating," from floter "to float" (of Germanic origin; see float) + -aison, from Latin -ation(em). Spelled flotsen till mid-19c. when it altered, perhaps under influence of many English words in -some.

In British law, flotsam are goods found floating on the sea as a consequence of a shipwreck or action of wind or waves; jetsam are things cast out of a ship in danger of being wrecked, and afterward washed ashore, or things cast ashore by the sailors. Whatever sinks is lagan. Figurative use for "odds and ends" attested by 1861.
flounce (v.) Look up flounce at Dictionary.com
1540s, "to dash, plunge, flop," perhaps from Scandinavian (compare dialectal Swedish flunsa "to plunge," Norwegian flunsa "to hurry," but first record of these is 200 years later than the English word), said to be of imitative origin. Spelling likely influenced by bounce. Notions of "anger, impatience" began to adhere to the word 18c. Related: Flounced; flouncing. As a noun, from 1580s as a motion.
flounce (n.) Look up flounce at Dictionary.com
"wide ruffle," 1713, from Middle English frounce "pleat, wrinkle, fold" (late 14c.), from Old French fronce "line, wrinkle; pucker, crease, fold," from Frankish *hrunkjan "to wrinkle," from Proto-Germanic *hrunk-. Influenced in form by flounce (v.).
flounder (v.) Look up flounder at Dictionary.com
1590s, perhaps an alteration of founder (q.v.), influenced by Dutch flodderen "to flop about," or native verbs in fl- expressing clumsy motion. Figurative use is from 1680s. Related: Floundered; floundering. As a noun derived from this sense, from 1867.
flounder (n.) Look up flounder at Dictionary.com
flatfish, c.1300, from Anglo-French floundre, from Old North French flondre, from Old Norse flydhra; related to Middle Low German vlundere, Danish flynder; ultimately cognate with Greek platys "flat, wide, broad" (see plaice (n.)).
flour (n.) Look up flour at Dictionary.com
early 13c., flur "flower" (see flower (n.)); meaning "finer portion of ground grain" is mid-13c., from the notion of flour as the "finest part" of meal (compare French fleur de farine), as distinguished from the coarser parts (meal). Spelled flower until flour became the accepted form c.1830 to end confusion.
flour (v.) Look up flour at Dictionary.com
"to sprinkle with flour," 1650s, from flour (n.). Related: Floured; flouring.
flourish (v.) Look up flourish at Dictionary.com
c.1300, "to blossom, grow," from Old French floriss-, stem of florir "blossom, flower, bloom, flourish," from Latin florere "to bloom, blossom, flower," figuratively "to flourish, be prosperous," from flos "a flower" (see flora).

Metaphoric sense of "thrive" is mid-14c. Meaning "to brandish (a weapon)" first attested late 14c. Related: Flourished; flourishing.
flourish (n.) Look up flourish at Dictionary.com
c.1500, "a blossom," from flourish (v.). Meaning "ostentatious waving of a weapon" is from 1550s; that of "literary or rhetorical embellishment" is from c.1600.
flout (v.) Look up flout at Dictionary.com
1550s, perhaps a special use of Middle English flowten "to play the flute" (compare Middle Dutch fluyten "to play the flute," also "to jeer"). Related: Flouted; flouting.
flow (v.) Look up flow at Dictionary.com
Old English flowan "to flow, stream, issue; become liquid, melt; abound, overflow" (class VII strong verb; past tense fleow, past participle flowen), from Proto-Germanic *flo- (cognates: Middle Dutch vloyen, Dutch vloeien "to flow," Old Norse floa "to deluge," Old High German flouwen "to rinse, wash"), probably from PIE *pleu- "flow, float" (see pluvial). The weak form predominated from 14c., but strong past participle flown is occasionally attested through 18c. Related: Flowed; flowing.
flow (n.) Look up flow at Dictionary.com
mid-15c., "action of flowing," from flow (v.). Meaning "amount that flows" is from 1807. Flow chart attested from 1920.
flower (n.) Look up flower at Dictionary.com
c.1200, from Old French flor "flower, blossom; heyday, prime; fine flour; elite; innocence, virginity" (Modern French fleur), from Latin florem (nominative flos) "flower" (source of Italian fiore, Spanish flor; see flora).

Modern spelling is 14c. Ousted Old English cognate blostm (see blossom (n.)). Also used from 13c. in sense of "finest part or product of anything" and from c.1300 in the sense of "virginity." Flower children "gentle hippies" is from 1967.
flower (v.) Look up flower at Dictionary.com
c.1200, "be vigorous, prosper, thrive," from flower (n.). Of a plant or bud, "to blossom," c.1300. Related: Flowered; flowering.
flowerpot (n.) Look up flowerpot at Dictionary.com
1590s, from flower (n.) + pot (n.1).
flowery (adj.) Look up flowery at Dictionary.com
mid-14c., from flower (n.) + -y (2). Related: Floweriness.