phrase preceded by one, two, three, etc., and signifying the time of day as shown by the face of a clock, c. 1720, an abbreviation of of the clock, from Middle English of the clokke (late 14c.). See O + clock (n.). The use of clock hand positions to describe vector directions or angles is from late 18c.
The Court dinner-hour, in the reign of George III., was at the Hanoverian hour of four o'clock. During the reign of George IV. it gradually crept up to six o'clock, and finally became steady at the Indian hour of seven, and so remained until the reign of Her Most gracious Majesty, when the formal Court dinner-hour became eight o'clock. These innovations on the national hours of meals did not meet the approval of the medical faculty, and in consequence a dinette at two o'clock was prescribed. This has ever since been the favourite Court meal, being in reality a substantial hot repast, which has exploded the old-fashioned luncheon of cold viands. [The Queen newspaper, London, quoted in Imperial Dictionary, 1883]
"the middle of the night, 12 o'clock at night," Old English mid-niht, or middre niht (with dative of adjective). See mid (adj.) + night. Compare similar formation in Old High German mittinaht, German Mitternacht. Midnight oil symbolizing "late night work" is attested from 1630s.
"1 more than four; the number which is one more than four; a symbol representing this number;" Old English fif "five," from Proto-Germanic *fimfe (source also of Old Frisian fif, Old Saxon fif, Dutch vijf, Old Norse fimm, Old High German funf, Gothic fimf), from PIE root *penkwe- "five." The lost *-m- is a regular development (compare tooth).
Five-and-ten (Cent Store) is from 1880, American English, with reference to prices of goods for sale. Five-star (adj.) is from 1913 of hotels, 1945 of generals. Slang five-finger discount "theft" is from 1966. The original five-year plan was 1928 in the U.S.S.R. Five o'clock shadow attested by 1937.
[under picture of a pretty girl] "If I were a man I'd pay attention to that phrase '5 O'Clock Shadow.' It's that messy beard growth which appears prematurely about 5 P.M." [advertisement for Gem razors and blades in Life magazine, May 9, 1938]
mid-12c., non "midday," in exact use, "12 o'clock p.m.," also "midday meal," from Old English non "3 o'clock p.m., the ninth hour from sunrise," also "the canonical hour of nones," from Latin nona hora "ninth hour" of daylight, by Roman and ecclesiastical reckoning about 3 p.m., from nona, fem. singular of nonus "ninth," contracted from *novenos, from novem "nine" (see nine).
The sense shift from "3 p.m." to "12 p.m." began during 12c., and various reasons are given for it, such as unreliability of medieval time-keeping devices and the seasonal elasticity of the hours of daylight in northern regions. In monasteries and on holy days, fasting ended at nones, which perhaps offered another incentive to nudge it up the clock. Or perhaps the sense shift was based on an advance in the customary time of the (secular) midday meal. Whatever the cause, the meaning change from "ninth hour" to "sixth hour" seems to have been complete by 14c. (the same evolution is in Dutch noen).
From 17c. to 19c., noon sometimes also meant "midnight" (the noon of the night).
"having an air of distinction," 1813 (in Byron), from French distingué, literally "distinguished," past participle of distinguer "to separate between, keep separate, mark off" (see distinguish).
The girls I knew had sad and sullen gray faces
With distingué traces
That used to be there — You could see where they'd been washed away
By too many through the day
Twelve o'clock tales.
["Lush Life," Billy Strayhorn, age 17]
There was a verb distingue (Middle English distinguen, mid-14c., "to divide or subdivide, discern, perceive"), from Old French distinguer, but it has not survived.
c. 1300, "first big meal of the day" (eaten between 9 a.m. and noon), from Old French disner "breakfast" (11c.), noun use of infinitive disner (Modern French dîner) "take the first meal of the day," from stem of Gallo-Roman *desjunare "to break one's fast," from Vulgar Latin *disjejunare, from dis- "undo, do the opposite of" (see dis-) + Late Latin jejunare "to fast," from Latin iejunus "fasting, hungry, not partaking of food" (see jejune).
Always used in English for the main meal of the day, but the time of that has gradually shifted later.
In medieval and modern Europe the common practice, down to the middle of the eighteenth century, was to take this meal about midday, or in more primitive times even as early as 9 or 10 A.M. In France, under the old régime, the dinner-hour was at 2 or 3 in the afternoon; but when the Constituent Assembly moved to Paris, since it sat until 4 or 5 o'clock, the hour for dining was postponed. The custom of dining at 6 o'clock or later has since become common, except in the country, where early dinner is still the general practice. [Century Dictionary, 1897]
The change from midday to evening began with the fashionable classes. Compare dinette.
Dinner-time is attested from late 14c.; dinner-hour is from 1750. Dinner-table is from 1784; dinner-jacket from 1852; dinner-party by 1780. Childish reduplication din-din is attested from 1905.
1850, American English, possibly an alteration of brother, or from British colloquial butty "companion" (1802), itself perhaps a variant of booty in booty fellow "confederate who shares plunder" (1520s). But butty, meaning "work-mate," also was a localized dialect word in England and Wales, attested since 18c., and long associated with coal miners. Short form bud is attested from 1851. Reduplicated form buddy-buddy (adj.) attested by 1952, American English.
Lenny Kent, a long-time fave here, is really in his element. ... After four weeks here he's got everyone in town saying, "Hiya, Buddy, Buddy" with a drawl simulating his. [Review of Ned Schuyler's 5 O'Clock Club, Miami Beach, Fla., Billboard, Nov. 12, 1949]
Buddy system attested from 1920.
"1 more than nine, twice five; the number which is one more than nine; a symbol representing this number;" Old English ten (Mercian), tien (West Saxon), adjective and noun, from Proto-Germanic *tehun (source also of Old Saxon tehan, Old Norse tiu, Danish ti, Old Frisian tian, Old Dutch ten, Dutch tien, Old High German zehan, German zehn, Gothic taihun "ten"), from PIE root *dekm- "ten."
Meaning "ten o'clock" is from 1712. Tenner "ten-pound note" is slang first recorded 1861; as "ten-dollar bill," 1887 (ten-spot in this sense dates from 1848). The Texan's exaggerated ten-gallon hat is from 1919. The ten-foot pole that you wouldn't touch something with (1909) was originally a 40-foot pole; the notion is of keeping one's distance, as in the advice to use a long spoon when you dine with the devil. Ten-four "I understand, message received," is attested in popular jargon from 1962, from citizens band and emergency dispatch radio 10-code (in use in U.S. by 1950).