Old English middel, "equally distant from extremes or limits; intermediate," from Proto-West Germanic *midla- (source also of Old Frisian middel, Old Saxon middil, Middle Low German, Dutch middel, Old High German mittil, German mittel), from Proto-Germanic *medj, from PIE root *medhyo- "middle."
Middle finger "the third finger" (counting the thumb as the first) so called from late Old English. Middle school is attested from 1838, originally "middle-class school, school for middle-class children;" the sense in reference to a school for grades between elementary and high school is from 1960. Middle management, the level below senior management, is by 1941.
Middle-of-the-road in the figurative sense is attested from 1894, originally political; edges of a dirt road can be washed out and thus are less safe, but the notion here probably is of the middle as "less exposed to ambush." Middle way in the figurative sense of "path of moderation" is from c. 1200. Middle ground as "place of moderation or compromise between extremes" is by 1961. Middle-sized "of medium size" is by 1620s.
In U.S. history, the Middle States (1784) were those between New England and the South (New York, New Jersey, Pennsylvania, Delaware). Middle America for "the 'silent majority,' the generally conservative middle class regarded as a homogeneous group" is by 1968.
"point or part equally distant from the extremes, limits, or extremities," Old English middel, from middle (adj.). As "middle part of the human body" in Old English. From c. 1300 as "the second of three."
"the earth regarded as placed midway between heaven and hell or the abode of the gods and the underworld," late 13c., from middle (adj.) + earth. Altered from earlier middel-erd (late 12c.), midden-erd, itself an alteration (by association with Middle English eard "dwelling") of Old English middangeard (see Midgard).
According to Mr. H.A. Hamilton, in his "Quarter Sessions from Queen Elizabeth," the practice of giving children two Christian names was unknown in England before the period of the Stuarts, was rarely adopted down to the time of the Revolution, and never became common until after the Hanoverian family was seated on the throne. "In looking through so many volumes of county records," he says, "I have, of course, seen many thousands and tens of thousands of proper names, belonging to men of all ranks and degrees,—to noblemen, justices, jurymen, witnesses, sureties, innkeepers, hawkers, paupers, vagrants, criminals, and others,—and in no single instance, down to the end of the reign of Anne, have I noticed any person bearing more than one Christian name ...." [Walsh]
"the middle period in the history of the English language," 1830; see middle (adj.) + English (n.). The term comes from Jakob Grimm's division of Germanic languages into Old, Middle and New in "Deutsche Grammatik" (1819). But for English he retained Anglo-Saxon, then already established, for what we call Old English, and used Old English for what we call early Middle English. Thus his Mittelenglisch, and the Middle English of mid-19th century English writers, tends to refer to the period c. 1400 to c. 1550. The confusion was sorted out, and the modern terminology established (with Middle English for the language from c. 1100 to c. 1500), mostly in the 1870.
in the trading sense, "contractor, negotiator, broker," especially "one who buys merchandise in bulk and sells it in smaller quantities to retailers or other traders," 1795, from middle (adj.) + man (n.). From mid-15c. as the name of some type of workman in wire-making. From 1741 as "one who takes a middle course." In minstrel shows, "the man who sits in the middle of the semicircle of performers and leads the dialogue between songs," by 1870.
"medium in rank, condition, or degree; intermediate," 1540s, from Middle English medlinge "intermediate between two things" (late 14c.), from middle (adj.) + present-participle suffix -ing (2). Used in trade to designate the second of three grades of goods. Hence "only medium, neither good nor bad" (1650s). As an adverb, "tolerably, passably," by 1719.