bear (n.)youdaoicibaDictYouDict[bear 词源字典]
Old English bera "bear," from Proto-Germanic *beron, literally "the brown (one)" (cognates: Old Norse björn, Middle Dutch bere, Dutch beer, Old High German bero, German Bär), from PIE *bher- (3) "bright, brown" (see brown (adj.)).

Greek arktos and Latin ursus retain the PIE root word for "bear" (*rtko; see Arctic), but it is believed to have been ritually replaced in the northern branches because of hunters' taboo on names of wild animals (compare the Irish equivalent "the good calf," Welsh "honey-pig," Lithuanian "the licker," Russian medved "honey-eater"). Others connect the Germanic word with Latin ferus "wild," as if it meant "the wild animal (par excellence) of the northern woods."

Symbolic of Russia since 1794. Used of uncouth persons since 1570s. Stock market meaning "speculator for a fall" is 1709 shortening of bearskin jobber (from the proverb sell the bearskin before one has caught the bear); i.e. "one who sells stock for future delivery, expecting that meanwhile prices will fall." Paired with bull from c. 1720. Bear claw as a type of large pastry is from 1942, originally chiefly western U.S.[bear etymology, bear origin, 英语词源]
best (adj.)youdaoicibaDictYouDict
Old English beste, reduced by assimilation of -t- from earlier Old English betst "best, first, in the best manner," originally superlative of bot "remedy, reparation," the root word now only surviving in to boot (see boot (n.2)), though its comparative, better, and superlative, best, have been transferred to good (and in some cases well). From Proto-Germanic root *bat-, with comparative *batizon and superlative *batistaz (cognates: Old Frisian, Old Saxon, Middle Dutch best, Old High German bezzist, German best, Old Norse beztr, Gothic batists).
The best-laid schemes o' mice an' men
Gang aft agley,
An' lea'e us nought but grief an' pain,
For promis'd joy!

[Burns]
Best-seller as short for "best-selling book" is from 1902, apparently originally in the publishing trade; best friend was in Chaucer (late 14c.). Best girl is first attested 1881, American English; best man is 1814, originally Scottish, replacing groomsman. To be able to do something with the best of them is recorded by 1748.
coast (n.)youdaoicibaDictYouDict
"margin of the land," early 14c.; earlier "rib as a part of the body" (early 12c.), from Old French coste "rib, side, flank; slope, incline;" later "coast, shore" (12c., Modern French côte), from Latin costa "a rib," perhaps related to a root word for "bone" (compare Old Church Slavonic kosti "bone," also see osseous).

Latin costa developed a secondary sense in Medieval Latin of "the shore," via notion of the "side" of the land, as well as "side of a hill," and this passed into Romanic (Italian costa "coast, side," Spanish cuesta "slope," costa "coast"), but only in the Germanic languages that borrowed it is it fully specialized in this sense (Dutch kust, Swedish kust, German Küste, Danish kyst). French also used this word for "hillside, slope," which led to verb meaning "sled downhill," first attested 1775 in American English. Expression the coast is clear (16c.) is an image of landing on a shore unguarded by enemies.
kiss (v.)youdaoicibaDictYouDict
Old English cyssan "to kiss," from Proto-Germanic *kussjan (cognates: Old Saxon kussian, Old Norse kyssa, Old Frisian kessa, Middle Dutch cussen, Dutch, Old High German kussen, German küssen, Norwegian and Danish kysse, Swedish kyssa), from *kuss-, probably ultimately imitative of the sound. Related: Kissed; kissing. For vowel evolution, see bury. There appears to be no common Indo-European root word for "kiss," though suggestions of a common ku- sound may be found in the Germanic root and Greek kynein "to kiss," Hittite kuwash-anzi "they kiss," Sanskrit cumbati "he kisses."
Kissing, as an expression of affection or love, is unknown among many races, and in the history of mankind seems to be a late substitute for the more primitive rubbing of noses, sniffing, and licking. [Buck, p.1113]
Some languages make a distinction between the kiss of affection and that of erotic love (compare Latin saviari "erotic kiss," vs. osculum, literally "little mouth"). French embrasser "kiss," but literally "embrace," came about in 17c. when the older word baiser (from Latin basiare) acquired an obscene connotation. Insulting invitation kiss my ass is at least from 1705, but probably much older (see "The Miller's Tale").
lac (n.)youdaoicibaDictYouDict
"red resinous substance," 1550s (perhaps via Middle French lacce), earlier lacca (early 15c., from Medieval Latin form lacca), from Persian lak, from Hindi lakh (Prakrit lakkha), from Sanskrit laksha "red dye," of uncertain origin. According to Klein, literally "one hundred thousand," in reference to the insects that gather in great numbers on the trees and make the resin run out. But others say lakh is an alteration of Sanskrit rakh, from an IE root word for "color, dye" [Watkins]. Still another guess is that Sanskrit laksha is related to English lax, lox "salmon," and the substance was perhaps originally so called from being somewhat the color of salmon [Barnhart].
lusty (adj.)youdaoicibaDictYouDict
early 13c., "joyful, merry," from lust + -y (2). It largely has escaped the Christianization and denigration of its root word. The sense of "full of healthy vigor" is from late 14c.; that of "full of desire" is attested from c. 1400. Related: Lustily; lustiness.
niggard (n.)youdaoicibaDictYouDict
"mean person, miser," late 14c., nygart, of uncertain origin. The suffix suggests French origin (see -ard), but the root word is possibly from earlier nig "stingy" (c. 1300), perhaps from a Scandinavian source related to Old Norse hnøggr "stingy," from Proto-Germanic *khnauwjaz (source of Swedish njugg "close, careful," German genau "precise, exact"), and to Old English hneaw "stingy, niggardly," which did not survive in Middle English.
red (adj.1)youdaoicibaDictYouDict
Old English read "red," from Proto-Germanic *raudaz (cognates: Old Norse rauðr, Danish rød, Old Saxon rod, Old Frisian rad, Middle Dutch root, Dutch rood, German rot, Gothic rauþs). As a noun from mid-13c.

The Germanic words are from PIE root *reudh- "red, ruddy" (cognates: Latin ruber, also dialectal rufus "light red," mostly of hair; Greek erythros; Sanskrit rudhira-; Avestan raoidita-; Old Church Slavonic rudru, Polish rumiany, Russian rumjanyj "flushed, red," of complexions, etc.; Lithuanian raudas; Old Irish ruad, Welsh rhudd, Breton ruz "red"). The only color for which a definite common PIE root word has been found. The initial -e- in the Greek word is because Greek tends to avoid beginning words with -r-.

Along with dead, bread (n.), lead (n.1), the vowel shortened in Middle English. The surname Read/Reid retains the original Old English long vowel pronunciation and is the corresponding surname to Brown-, Black, White.

The color designation of Native Americans in English from 1580s. The color as characteristic of "British possessions" on a map is attested from 1885. Red-white-and-blue in reference to American patriotism, from the colors of the flag, is from 1840; in a British context, in reference to the Union flag, 1852. The red flag was used as a symbol of defiance in battle on land or sea from c. 1600. To see red "get angry" is an American English expression first recorded 1898. Red rover, the children's game, attested from 1891. Red light as a sign to stop is from 1849, long before traffic signals. As the sign of a brothel, it is attested from 1899. As a children's game (in reference to the traffic light meaning) it is recorded from 1953.

Red-letter day (late 14c.) was originally a saint's day, marked on church calendars in red letters. Red ball signifying "express" in railroad jargon is 1904, originally (1899) a system of moving and tracking freight cars. Red dog, type of U.S. football pass rush, is recorded from 1959. Red meat is from 1808. Red shift in spectography is first recorded 1923. Red carpet "sumptuous welcome" is from 1934, but the custom for dignitaries is described as far back as Aeschylus ("Agamemnon"); it also was the name of a type of English moth.
responsible (adj.)youdaoicibaDictYouDict
1590s, "answerable" (to another, for something), from obsolete French responsible (13c., Modern French responsable, as if from Latin *responsabilis), from Latin respons-, past participle stem of respondere "to respond" (see respond). Meaning "accountable for one's actions" is attested from 1640s; that of "reliable, trustworthy" is from 1690s. Retains the sense of "obligation" in the Latin root word. Related: Responsibly.
rivalry (n.)youdaoicibaDictYouDict
1590s; from rival + -ry. Shakespeare has rivality ("Antony and Cleopatra"), but from the secondary sense of the root word and meaning "partnership, equality in rank."
sister (n.)youdaoicibaDictYouDict
mid-13c., from Old English sweostor, swuster "sister," or a Scandinavian cognate (Old Norse systir, Swedish syster, Danish søster), in either case from Proto-Germanic *swestr- (cognates: Old Saxon swestar, Old Frisian swester, Middle Dutch suster, Dutch zuster, Old High German swester, German Schwester, Gothic swistar).

These are from PIE *swesor, one of the most persistent and unchanging PIE root words, recognizable in almost every modern Indo-European language (Sanskrit svasar-, Avestan shanhar-, Latin soror, Old Church Slavonic, Russian sestra, Lithuanian sesuo, Old Irish siur, Welsh chwaer, Greek eor). French soeur "a sister" (11c., instead of *sereur) is directly from Latin soror, a rare case of a borrowing from the nominative case.

According to Klein's sources, probably from PIE roots *swe- "one's own" + *ser- "woman." For vowel evolution, see bury. Used of nuns in Old English; of a woman in general from 1906; of a black woman from 1926; and in the sense of "fellow feminist" from 1912. Meaning "female fellow-Christian" is from mid-15c. Sister act "variety act by two or more sisters" is from vaudeville (1908).
stag (n.)youdaoicibaDictYouDict
late 12c., probably from Old English stagga "a stag," from Proto-Germanic *stag-, from PIE *stegh- "to prick, sting" (see sting (v.)). The Old Norse equivalent was used of male foxes, tomcats, and dragons; and the Germanic root word perhaps originally meant "male animal in its prime." Meaning "pertaining to or composed of males only" (stag party) is American English slang from 1848. Stag film "pornographic movie" is attested from 1968. Stag beetle, so called for its" horns," is from 1680s.
water (n.1)youdaoicibaDictYouDict
Old English wæter, from Proto-Germanic *watar (cognates: Old Saxon watar, Old Frisian wetir, Dutch water, Old High German wazzar, German Wasser, Old Norse vatn, Gothic wato "water"), from PIE *wod-or, from root *wed- (1) "water, wet" (cognates: Hittite watar, Sanskrit udrah, Greek hydor, Old Church Slavonic and Russian voda, Lithuanian vanduo, Old Prussian wundan, Gaelic uisge "water;" Latin unda "wave").

To keep (one's) head above water in the figurative sense is recorded from 1742. Water cooler is recorded from 1846; water polo from 1884; water torture from 1928. Linguists believe PIE had two root words for water: *ap- and *wed-. The first (preserved in Sanskrit apah as well as Punjab and julep) was "animate," referring to water as a living force; the latter referred to it as an inanimate substance. The same probably was true of fire (n.).