"long and loose-jointed," by 1812, from Scottish and Northern English gang (v.) "to walk, go," which is a survival of Old English gangan, which is related to gang (n.). The form of the word is that of a present-participle adjective from a frequentative verb (as in fondling, trampling), but no intermediate forms are known. The sense extension would seem to be via some notion involving looseness in walking.
GANGLING. Tall, slender, delicate, generally applied to plants. Warw. [James O. Halliwell, "A Dictionary of Archaic and Provincial Words," 1846]
c. 1400, mediocrite, "moderation; intermediate state or amount," from Latin mediocritatem (nominative mediocritas) "a middle state, middling condition, medium," from mediocris "of middling height or state, moderate, ordinary," figuratively "mediocre, mean, inferior," literally "halfway up a mountain" (see mediocre). Neutral at first; disparaging sense "quality of being moderate or middling in ability, accomplishment, etc." began to predominate from late 16c. The meaning "person of mediocre abilities or attainments" is from 1690s. Before the tinge of disparagement crept in, another name for the Golden Mean was golden mediocrity.
Middle English sapi, of a tree or of wood, "full of sap," from Late Old English sæpig, from sæp "sap of a plant" (see sap (n.1)). The colloquial figurative sense, in reference to persons, etc., "foolish, foolishly sentimental" (1660s) might have developed from an intermediate sense of "too wet, sodden, soggy" (late 15c.), or it might have come from sappy as "containing sapwood" (mid-15c.); compare sap (n.2). Or it might be from the notion of "green, juvenile," like a sapling tree. Earlier, now obsolete, figurative senses were "full of vitality" (1550s) and "immature" (1620s). Related: Sappily; sappiness.
"not present or found, absent," 1520s, present-participle adjective from miss (v.). Military sense of "not present after a battle but not known to have been killed or captured" is from 1845. As a noun by 1855.
Missing link was used in various figurative senses before is attested 1846 in reference to forms of plant and animal life [Chambers, "Vestiges of the Natural History of Creation"]; in reference to a hypothetical creature between man and the apes, as a component of Darwin's theory of evolution, by 1860.
But then, where are the missing links in the chain of intellectual and moral being? What has become of the aspirants to the dignity of manhood whose development was unhappily arrested at intermediate points between the man and the monkey? It will not be doubted, we presume, that there exists at present an enormous gap between the intellectual capabilities of the lowest race of men and those of the highest race of apes; and if so, we ask again, why should the creatures intermediate to them—exalted apes or degraded men—have been totally exterminated, while their less worthy ancestors have successfully struggled through the battle of life? [William Hopkins, "Physical Theories of the Phenomena of Life," Fraser's Magazine, July, 1860]
In a popular religious tract of the late 1850s, "The Missing Link of the London Poor," the missing link was the Bible. Missing person, one who has disappeared and whose condition, whether alive or dead, is unknown, is by 1820.
"middle; being the middle part or midst; being between, intermediate," Old English mid, midd from Proto-Germanic *medja- (source also of Old Norse miðr, Old Saxon middi, Old Frisian midde, Middle Dutch mydde, Old High German mitti, German mitte, Gothic midjis "mid, middle"), from PIE root *medhyo- "middle."
By late Middle English probably felt as a prefix only, and now surviving in English only as a prefix (mid-air, midstream, etc.). Prefixed to months, seasons, etc. from late Old English. As a preposition, "in the middle of, amid" (c. 1400) it is from in midde or a shortened form of amid (compare midshipman) and sometimes is written 'mid.
c. 1600, "indifference to pain," from French indolence (16c.) or directly from Late Latin indolentia "freedom from pain, insensibility," abstract noun from Latin indolentem (nominative indolens) "insensitive to pain," from in- "not, opposite of, without" (see in- (1)) + dolentem (nominative dolens) "grieving," present participle of dolere "suffer pain, grieve" (see doleful). Originally of prisoners under torture, etc. The intermediate sense "state of rest or ease neither pleasant nor painful" (1650s) is now obsolete as well; main modern sense of "laziness, love of ease" (1710) perhaps reflects the notion of avoiding trouble (compare taking pains "working hard, striving (to do)").
The Castle hight of Indolence,
And its false Luxury;
Where for a little Time, alas!
We liv'd right jollity.
[Thomson, "The Castle of Indolence," 1748]
1580s, "a middle ground, quality, or degree; that which holds a middle place or position," from Latin medium "the middle, midst, center; interval," noun use of neuter of adjective medius "in the middle, between; from the middle" (from PIE root *medhyo- "middle").
Many of the secondary senses are via the notion of "intervening substance through which a force or quality is conveyed" (1590s) and "intermediate agency, channel of communication" (c. 1600). From the former, via application to air, etc., comes the sense of "one's environment or conditions" (1865). From the latter comes the sense of "a print publication" (1795) which later grew into the meaning in media.
In spiritualism, "person who conveys spiritual messages," by 1853. In painting, in reference to oil, watercolor, etc., by 1854. The notion is "liquid with which pigments are ground or mixed to give them desired fluidity." Happy medium is the "golden mean," Horace's aurea mediocritas.
1859, slang shortening of public house (see public (adj.)), which originally meant "any building open to the public" (1570s), then "inn that provides food and is licensed to sell ale, wine, and spirits" (1660s), and finally "tavern" (1768). Simple public (n.) as short for public house is attested from 1709 and might have been the intermediate form. Pub crawl is attested by 1910 in British slang. Pub rock is from 1973 in England; popular in U.S. from 1976.
When, in the late '60s, rock 'n' roll suddenly became rock, there sprang up a network of bands that sought to preserve the old styles, that resisted the trend toward larger and larger concert halls. Because these groups preferred to play one-nighters on Britain's club circuit, their music came to be known as "pub rock." ["U.S. gets 'pub rock,'" Washington Post article in Newark (Ohio) Advocate, April 1, 1976]
"inside diameter of a gun barrel," 1580s, from French calibre (by mid-16c., perhaps late 15c.), often said to be ultimately from Arabic qalib "a mold for casting." Barnhart remarks that Spanish calibre, Italian calibro "appear too late to act as intermediate forms" between the Arabic word and the French.
But English Words of Arabic Ancestry finds that the idea of an Arabic source "comes with no evidence and no background historical context to support it. It is far more likely that the word was formed in French" from Medieval Latin qua libra "of what weight" (a theory first published 19c. by Mahn), from fem. ablative of quis (from PIE root *kwo-, stem of relative and interrogative pronouns) + ablative of libra "balance" (see Libra).
In U.S., expressed in decimal parts of an inch (.44-caliber = ".44-inch caliber"). The earliest sense in English is a figurative one, "degree of merit or importance" (1560s), from French. Later, figuratively, "the capacity of one's mind, one's intellectual endowments."
c. 1300, "incantation, magic charm," from Old French charme (12c.) "magic charm, magic spell incantation; song, lamentation," from Latin carmen "song, verse, enchantment, religious formula," from canere "to sing" (from PIE root *kan- "to sing"), with dissimilation of -n- to -r- before -m- in intermediate form *canmen (for a similar evolution, see Latin germen "germ," from *genmen). The notion is of chanting or reciting verses of magical power.
A yet stronger power than that of herb or stone lies in the spoken word, and all nations use it both for blessing and cursing. But these, to be effective, must be choice, well knit, rhythmic words (verba concepta), must have lilt and tune; hence all that is strong in the speech wielded by priest, physician, magician, is allied to the forms of poetry. [Jakob Grimm, "Teutonic Mythology" (transl. Stallybrass), 1883]
Sense of "pleasing quality, irresistable power to please and attract" evolved by 17c. From 1590s as "any item worn to avert evil;" meaning "small trinket fastened to a watch-chain, etc." first recorded 1865. Quantum physics sense is from 1964. Charm-bracelet is from 1941; charm-school from 1919. To work like a charm (figuratively) is recorded by 1824.