英语词源字典 - 在线词源网站

by (prep.)[by 词源字典]: Old English be- (unstressed) or bi (stressed) "near, in, by, during, about," from Proto-Germanic *bi "around, about" (cognates: Old Saxon and Old Frisian bi "by near," Middle Dutch bie, Dutch bij, German bei "by, at, near," Gothic bi "about"), from *umbi (cognate with second element in PIE *ambhi "around;" see ambi-).

Originally an adverbial particle of place, in which sense it is retained in place names (Whitby, Grimsby, etc.). Elliptical use for "secondary course" (opposed to main, as in byway, also compare by-blow "illegitimate child," 1590s) was in Old English. This also is the sense of the second by in the phrase by the by (1610s). By the way literally means "in passing by" (mid-14c.); used figuratively to introduce a tangential observation by 1540s.

Phrase by and by (early 14c.) originally meant "one by one," modern sense is from 1520s. By and large (1660s) originally was nautical, "sailing to the wind and off it," hence "in one direction then another."[by etymology, by origin, 英语词源]
kathenotheism (n.): "a form of polytheism characteristic of the Vedic religion, in which one god at a time is considered supreme," 1865, coined in German by Max Müller from Greek kath' hena "one by one" + theism. Müller also coined henotheism (1860), from Greek henos "one," for "faith in a single god" as distinguished from exclusive belief in only one god, in writings on early Hebrew religion.
pick (v.): early 13c., picken "to peck;" c. 1300, piken "to work with a pick," probably representing a fusion of Old English *pician "to prick," (implied by picung "a piercing, pricking," an 8c. gloss on Latin stigmata) with Old Norse pikka "to prick, peck," both from a Germanic root (source also of Middle Dutch picken, German picken "to pick, peck"), perhaps imitative. Influence from Middle French piquer "to prick, sting" (see pike (n.2)) also is possible, but that French word generally is not considered a source of the English word. Related: Picked; picking.

Meaning "to eat with small bites" is from 1580s. The meaning "to choose, select, pick out" emerged late 14c., from earlier meaning "to pluck with the fingers" (early 14c.). Sense of "to rob, plunder" (c. 1300) weakened to a milder sense of "steal petty things" by late 14c. Of forcing locks with a pointed tool, by 1540s. Meaning "to pluck (a banjo)" is recorded from 1860. To pick a quarrel, etc. is from mid-15c.; to pick at "find fault with" is from 1670s. Pick on "single out for adverse attention" is from late 14c.; pick off "shoot one by one" is recorded from 1810; baseball sense of "to put out a runner on base" is from 1939. Also see pick up. To pick and choose "select carefully" is from 1660s (choose and pick is attested from c. 1400).
single (adj.): early 14c., "unmarried," from Old French sengle, sangle "alone, unaccompanied; simple, unadorned," from Latin singulus "one, one to each, individual, separate" (usually in plural singuli "one by one"), from sim- (stem of simplus; see simple) + diminutive suffix. Meaning "consisting of one unit, individual, unaccompanied by others" is from late 14c. Meaning "undivided" is from 1580s. Single-parent (adj.) is attested from 1966.
singular (adj.): mid-14c., "alone, apart; being a unit; special, unsurpassed," from Old French singuler "personal particular; distinctive; singular in number" (12c., Modern French singulier) or directly from Latin singularis "single, solitary, one by one, one at a time; peculiar, remarkable," from singulus (see single (adj.)). Meaning "remarkably good, unusual, rare, separated from others (by excellence), uncommon" is from c. 1400 in English; this also was a common meaning of Latin singularis.