late 13c., "furnace;" late 14c., "smoke vent of a fireplace, vertical structure raised above a house for smoke to escape to the open air;" from Old French cheminee "fireplace; room with a fireplace; hearth; chimney stack" (12c., Modern French cheminée), from Medieval Latin caminata "a fireplace," from Late Latin (camera) caminata "fireplace; room with a fireplace," from Latin caminatus, adjective of caminus "furnace, forge; hearth, oven; flue," from Greek kaminos "furnace, oven, brick kiln," which is of uncertain origin.
From the persistence of the medial i in OF. it is seen that the word was not an ancient popular word, but a very early adoption of caminata with subsequent phonetic evolution [OED]
Jamieson  notes that in vulgar use in Scotland it typically was pronounced "chimley." From the same source are Old High German cheminata, German Kamin, Russian kaminu, Polish komin. Chimney-corner "space beside a fireplace" is from 1570s.
The "sh" sound did not exist in Old French, therefore French scribes after the Norman conquest often represented it with -ssh- in medial and final positions, and sch- in initial positions (schape, schamful, schaft for shape, shameful, shaft). But the spelling -sh- has been standard since Caxton, probably as a worn-down form of Middle English -sch-.
In some East Anglian texts from 14c.-15c., x- is used (xal, xulde for shall, should), which would have given the language a very different look had it prevailed, but the London-based sh- ended up as the standard form. The same Germanic sound has become, by natural evolution, modern German and Dutch sch-, Scandinavian sk-.
late 15c., "any small charge over freight cost, payable by owners of goods to the master of a ship for his care of the goods," also "financial loss incurred through damage to goods in transit," from French avarie "damage to ship," and Italian avaria. A word from 12c. Mediterranean maritime trade (compare Spanish averia), of uncertain origin; sometimes traced to Arabic 'awariya "damaged merchandise." Dutch avarij, German haferei, etc., also are from Romanic languages. "Few words have received more etymological investigation" [OED].
Thus, when for the safety of a ship in distress any destruction of property is incurred, either by cutting away the masts, throwing goods overboard, or in other ways, all persons who have goods on board or property in the ship (or the insurers) contribute to the loss according to their average, that is, according to the proportionate value of the goods of each on board. [Century Dictionary]
The meaning developed to "equal sharing of loss by the interested parties." Transferred sense of "statement of a medial estimate, proportionate distribution of inequality among all," is first recorded 1735. The mathematical sense "a mean proportion arrived at by arithmetical calculation" is from 1755. Sports sense, of batting, attested by 1845, originally in cricket.
c. 1200, lafdi, lavede, from Old English hlæfdige (Northumbrian hlafdia, Mercian hlafdie), "mistress of a household, wife of a lord," apparently literally "one who kneads bread," from hlaf "bread" (see loaf (n.)) + -dige "maid," which is related to dæge "maker of dough" (which is the first element in dairy; see dey (n.1)). Also compare lord (n.)). Century Dictionary finds this etymology "improbable," and OED rates it "not very plausible with regard to sense," but no one seems to have a better explanation.
The medial -f- disappeared 14c. The word is not found outside English except where borrowed from it. Sense of "woman of superior position in society" is c. 1200; that of "woman whose manners and sensibilities befit her for high rank in society" is from 1861 (ladylike suggesting this sense is attested from 1580s, and ladily from c. 1400). Meaning "woman chosen as an object of chivalrous love" is from early 14c. Used commonly as an address to any woman since 1890s.
Applied since Old English to the Holy Virgin, hence many extended usages in plant names, place names, etc., from genitive singular hlæfdigan, which in Middle English merged with the nominative, so that lady- often represents (Our) Lady's, as in ladybug. Lady Day (late 13c.) was the festival of the Annunciation of the Virgin Mary (March 25). Ladies' man first recorded 1784; lady-killer "man supposed to be dangerously fascinating to women" is from 1811. Lady of pleasure recorded from 1640s. Lady's slipper as a type of orchid is from 1590s.
eighteenth letter of the English alphabet, traceable to Phoenician and always representing more or less the same sound, which in many languages is typically so resonant and continuous as to be nearly akin to the vowels, but in English is closer to -l-.
It was aspirated at the start of words (hr-) in Old English, as in Greek, but this was abandoned in English spelling and pronunciation by the end of the Old English period, but the rh- spelling survives in many words borrowed from Greek. In many languages and some dialects (e.g. Scottish) it is pronounced with a distinct trilling vibration of the tongue-tip, which gave it its ancient nickname of "the dog letter;" in other regional dialects (e.g. Boston) it is omitted unless followed by a vowel, while in others it is introduced artificially in pronunciation ("idear," "drawring").
If all our r's that are written are pronounced, the sound is more common than any other in English utterance (over seven per cent.); the instances of occurrence before a vowel, and so of universal pronunciation, are only half as frequent. There are localities where the normal vibration of the tip of the tongue is replaced by one of the uvula, making a guttural trill, which is still more entitled to the name of "dog's letter" than is the ordinary r; such are considerable parts of France and Germany; the sound appears to occur only sporadically in English pronunciation. [Century Dictionary]
Louise Pound ("The Humorous 'R'") notes that in British humorous writing, -ar- "popularly indicates the sound of the vowel in father" and formations like larf (for laugh) "are to be read with the broad vowel but no uttered r."
The moment we encounter the added r's of purp or dorg in our reading we know that we have to do with humor, and so with school-marm. The added consonants are supposed to be spoken, if the words are uttered, but, as a matter of fact, they are less often uttered than seen. The words are, indeed, largely visual forms; the humor is chiefly for the eye. [Louise Pound, "The Humorous 'R,'" American Mercury, October 1924]
She also quotes Henry James on the characteristic prominence of the medial -r- sound (which tends to be dropped in England and New England) in the speech of the U.S. Midwest, "under some strange impulse received toward consonantal recovery of balance, making it present even in words from which it is absent, bringing it in everywhere as with the small vulgar effect of a sort of morose grinding of the back teeth."
In a circle, meaning "registered (trademark)," attested by 1925. R&R "rest and relaxation," is attested by 1953, American English; R&B "rhythm and blues" (type of popular music) is attested by 1949, American English. Form three Rs, see Three Rs.