googol (n.)
number represented by 1 followed by 100 zeroes, 1940, in "Mathematics and the Imagination," a layman's book on mathematics written by U.S. mathematicians Edward Kasner (1878-1955) and James R. Newman, the word supposedly coined a year or two before by Kasner's 9- (or 8-) year-old nephew (unnamed in the book's account of the event), when asked for a name for an enormous number. Perhaps influenced by comic strip character Barney Google. Googolplex (10 to the power of a googol) coined at the same time, in the same way, with -plex.
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dinner (n.)

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.

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curfew (n.)

early 14c., curfeu, "evening signal, ringing of a bell at a fixed hour" as a signal to extinguish fires and lights, from Anglo-French coeverfu (late 13c.), from Old French cuevrefeu, literally "cover fire" (Modern French couvre-feu), from cuevre, imperative of covrir "to cover" (see cover (v.)) + feu "fire" (see focus (n.)). Related: Curfew-bell (early 14c.).

The medieval practice of ringing a bell (usually at 8 or 9 p.m.) as an order to bank the hearths and prepare for sleep was to prevent conflagrations from untended fires. The modern extended sense of "periodic restriction of movement" had evolved by 1800s.

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cotton-picking (adj.)

as a deprecatory term first recorded in a Bugs Bunny cartoon, but a similar noun cotton-picker meaning "contemptible person" dates to around 1919, perhaps with racist overtones that have faded over the years. Before mechanization, cotton picking was the most difficult labor on a plantation.

I drove out to a number of the farms near Denison and found many very young white children working all day in the hot sun picking and dragging sacks of cotton. In one field the labor corps consisted of one woman and six children, one of them 5 years, one 6 years, one 7 years, one 9 years, and two about 11. The father was plowing. The 5 and 6 year olds worked all day as did the rest. The 7-year-old said he picked 50 pounds a day and the 9 year old 75 pounds. (A good picker averages several hundred a day.) School begins late on account of the cotton picking, but the children nearly all prefer school to the picking. Picking hours are long, hot, and deadly monotonous. While the very young children seem to enjoy it, very soon their distaste for it grows into all-absorbing hatred for all work. ["Field Notes of Lewis W. Hine, Child-Labor Conditions in Texas," report to U.S. Congressional Commission on Industrial Relations, 1916]
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cloud nine (n.)
by 1950, sometimes also cloud seven (1956, perhaps by confusion with seventh heaven), American English, of uncertain origin or significance. Some connect the phrase with the 1895 International Cloud-Atlas (Hildebrandsson, Riggenbach and Teisserenc de Bort), long the basic source for cloud shapes, in which, of the ten cloud types, cloud No. 9, cumulonimbus, was the biggest, puffiest, most comfortable-looking. Shipley suggests the sense in this and other expressions might be because, "As the largest one-figure integer, nine is sometimes used for emphasis." The phrase might appear in the 1935 aviation-based play "Ceiling Zero" by Frank Wilbur Wead.
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poliomyelitis (n.)

1874, also polio-myelitis, coined by German physician Adolph Kussmaul (1822-1902) from Greek polios "grey" (from PIE root *pel- (1) "pale") + myelos "marrow" (a word of unknown origin) + -itis "inflammation." So called because the gray matter in the spinal cord is inflamed, which causes paralysis. The earlier name was infantile paralysis (1843).

In many respects, also, this affection resembles the acute spinal paralysis of infancy, which, from the researches of Charcot, Joffroy, and others, have been shown pathologically to be an acute myelitis of the anterior cornua. Hence, for these forms of paralysis, Professor Kussmaul suggests the name of 'poliomyelitis anterior.' [London Medical Record, Dec. 9, 1874]

Polioencephalitis (also poliencephalitis) "inflammation of the gray matter of the brain" is by 1885.

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redline (v.)

also red-line, "mark in red ink," 1820, from red (adj.1) + line (v.). Specific sense of "deny loans to certain neighborhoods based on ethnicity" is from 1973, on notion of lines drawn on maps. Used earlier in reference to insurance company practices (by 1956) and in World War II military slang in reference to a red line drawn through a soldier's name for some infraction, thus denying his pay. Related: Redlined; redlining.

Reports have been increasing here in the last few days to the effect that the American Automobile Association is "red lining" Warren County as a speed trap. [Park City Daily News, Bowling Green, Ky., March 9, 1956]
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libertine (n.)
late 14c., "a freedman, an emancipated slave," from Latin libertinus "condition of a freedman; member of a class of freedmen," from libertus "one's freedmen, emancipated person," from liber "free" (see liberal (adj.)).

Sense of "freethinker" is first recorded 1560s, from French libertin (1540s) originally the name given to certain pantheistic Protestant sects in France and the Low Countries. This sense partakes more of liberty and liberal than of the classical meaning (in Old French, libertin meant "Saracen slave converted to Christianity"). Meaning "dissolute or licentious person, man given to indulgence of lust" is first recorded 1590s; the darkening of meaning being perhaps due to misunderstanding of Latin libertinus in Acts vi:9. For "condition of being a libertine" 17c English tried libertinage; libertinism (from French libertinisme).
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tween (prep.)
also 'tween, c. 1300 as an abbreviation of between. As a noun meaning "child nearing puberty" (approximately ages 9 to 12), attested by 1988, in this case by influence of teen. Tolkien uses it in "Lord of the Rings" for "the irresponsible twenties between [Hobbit] childhood and coming of age at thirty-three." Earlier in this sense was subteen (1952). Related: Tweens. Tweenie or tweeny was a term (late 19c.-early 20c.) for "between-maid, a servant who assists two others" and was used in reference to other persons or objects in intermediary situations. And 'tween-age (adj.) was used in descriptions of clothing from 1937. Tween-ager is attested from 1946.
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prime (n.)

"earliest canonical hour of the day" (6 a.m.), from Old English prim and Old French prime and directly from Medieval Latin prima "the first service," from Latin prima hora "the first hour" (of the Roman day), from Latin primus "first, the first, first part" (see prime (adj.)).  (In classical Latin, the noun uses of the adjective meant "first part, beginning; leading place.")

By extension, "the first division of the day" 6 a.m. to 9 a.m. (early 13c.). The sense of "beginning of a period or course of events" is from late 14c. From the notion of "the period or condition of greatest vigor in life" (by 1530s) comes the specific sense "springtime of human life" (often meaning ages roughly 21 to 28) is from 1590s. Also from 1590s as "that which is best in quality, highest or most perfect state of anything." As "a prime number," by 1530s.

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