sleuthyoudaoicibaDictYouDict[sleuth 词源字典]
sleuth: [12] Sleuth originally meant ‘track, trail’ (‘John of Lorn perceived the hound had lost the sleuth’, John Barbour, The Bruce 1375). It was borrowed from Old Norse slóth ‘track, trail’, which was probably also the ultimate source of English slot ‘trail of an animal’ [16]. In the 14th century the compound sleuth-hound ‘bloodhound for tracking fugitives’ was coined. This was later shortened back to sleuth, and applied in 19th-century America to a ‘detective’.
=> slot[sleuth etymology, sleuth origin, 英语词源]
backtrack (v.)youdaoicibaDictYouDict
"retrace one's steps," figuratively, by 1896, from literal sense, with reference to hunted foxes, from back (adv.) + track (v.). Related: Backtracked; backtracking.
consumer (n.)youdaoicibaDictYouDict
early 15c., "one who squanders or wastes," agent noun from consume. In economic sense, "one who uses up goods or articles" (opposite of producer) from 1745. Consumer goods is attested from 1890. In U.S., consumer price index calculated since 1919, tracking "changes in the prices paid by urban consumers for a representative basket of goods and services" [Bureau of Labor Statistics]; abbreviation CPI is attested by 1971.
hot (adj.)youdaoicibaDictYouDict
Old English hat "hot, flaming, opposite of cold," also "fervent, fierce, intense, excited," from Proto-Germanic *haita- (cognates: Old Saxon and Old Frisian het, Old Norse heitr, Middle Dutch and Dutch heet, German heiß "hot," Gothic heito "heat of a fever"), from PIE root *kai- "heat" (cognates: Lithuanian kaistu "to grow hot").

The association of hot with sexuality dates back to c. 1500. Taste sense of "pungent, acrid, biting" is from 1540s. Sense of "exciting, remarkable, very good" is 1895; that of "stolen" is first recorded 1925 (originally with overtones of "easily identified and difficult to dispose of"); that of "radioactive" is from 1942.

Hot flashes in the menopausal sense attested from 1887. Hot air "unsubstantiated statements, boastful talk" is from 1900. Hot stuff for anything good or excellent is by 1889. Hot potato in figurative sense is from 1846. The hot and cold in hide-and-seek or guessing games are from hunting (1640s), with notion of tracking a scent.
PyoudaoicibaDictYouDict
a rare letter in the initial position in Germanic, in part because by Grimm's Law PIE p- became Germanic f-; even with the early Latin borrowings in Old English, -p- takes up 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 English vocabulary, and with C and S comprises nearly a third of the dictionary, a testimony to the flood of words that have entered the language since 1066 from Latin, Greek, and French.

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 see also to be P and Q (1610s), "to be excellent," a slang phrase said to derive from prime quality.
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.
track (v.)youdaoicibaDictYouDict
"to follow or trace the footsteps of," 1560s, from track (n.). Meaning "leave a footprint trail in dirt, mud, etc." is from 1838. Of film and TV cameras, 1959. Related: Tracked; tracking.