Etymology
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over (prep., adv.)

Old English ofer "beyond; above, in place or position higher than; upon; in; across, past; more than; on high," from Proto-Germanic *uberi (source also of Old Saxon obar, Old Frisian over, Old Norse yfir, Old High German ubar, German über, Gothic ufar "over, above"), from PIE root *uper "over."

As an adjective from Old English uffera. The senses of "past, done,  finished; through the whole extent, from beginning to end" are attested from late 14c. The sense of "so as to cover the whole surface" is from c. 1400. Meaning "leaning forward and down" is from 1540s. The meaning "recovered from" is from 1929. In radio communication, it is used to indicate the speaker has finished speaking (1926).

Above expresses greater elevation, but not necessarily in or near a perpendicular direction; over expresses perpendicularity or something near it: thus, one cloud may be above another, without being over it. Over often implies motion or extension where above would not; hence the difference in sense of the flying of a bird over or above a house, the hanging of a branch over or above a wall. In such uses over seems to represent greater nearness. [Century Dictionary]

Phrase over and above (mid-15c.) is pleonastic, for emphasis. Adjective phrase over-the-counter is attested from 1875, originally of stocks and shares. To be (someone) all over "be exactly what one expects of (someone)" is by 1721.

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fly-over (n.)
also flyover, 1901 of bridges, 1931, of aircraft flights, from fly (v.1) + over (adv.).
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sleep-over (n.)
1935, from verbal phrase; see sleep (v.) + over (adv.).
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walk-over (n.)
"easy victory," 1838, such as one that happens in the absence of competitors, when the solitary starter, being obliged to complete the event, can traverse the course at a walk. Transferred sense of "anything accomplished with great ease" is attested from 1902. To walk (all) over (someone) "treat with contempt" is from 1851.
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cross-over (n.)

also crossover, 1795, a term in calico-printing, "superimposed color in the form of stripes or crossbars," from the verbal phrase; see cross (v.) + over (adv.). From 1884 in railroading; from 1912 in biology. As a general adjective from 1893; specifically of musicians and genres from 1971.

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all-over (adj.)
"covering every part," 1859, from the adverbial phrase; see all + over (adv.). As a noun, by 1838 as the trade name for a button, etc., gilded on both sides rather than only the top. All-overish "generally, indefinitely indisposed" is from 1820. Related: All-overishness.
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over-age (adj.)

that is over a certain age," "1886, from over- + age (n.). Related: Over-aged (n.) "those who are too old" (late 15c.).

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stop-over (n.)
also stopover, 1881, from the verbal phrase, from stop (v.) + over (adv.).
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once-over (n.)

"glance, rapid inspection," 1913, American English, from once + over.

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going-over (n.)
1872 as "scolding;" 1919 as "inspection;" from verbal phrase; see going + over (adv.).
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