bypass n.

Old English be- (unstressed) or bi (stressed) "near, in, by, during, about," from Proto-Germanic *bi "around, about," in compounds often merely intensive (source also of Old Saxon and Old Frisian bi "by, near," Middle Dutch bie, Dutch bij, German bei "by, at, near," Gothic bi "about"), from PIE *bhi, reduced form of root *ambhi- "around."

As an adverb by c. 1300, "near, close at hand."

OED (2nd ed. print) has 38 distinct definitions of it as a preposition. Originally an adverbial particle of place, which sense survives in place names (Whitby, Grimsby, etc., also compare rudesby). Elliptical use for "secondary course" was in Old English (opposed to main, as in byway, also compare by-blow "illegitimate child," 1590s, Middle English loteby "a concubine," from obsolete lote "to lurk, lie hidden"). This also is the sense of the second by in the phrase by the by (1610s).

By the way literally means "along the way" (c. 1200), hence "in passing by," used figuratively to introduce a tangential observation ("incidentally") by 1540s. To swear by something or someone is in Old English, perhaps originally "in the presence of." Phrase by and by (early 14c.) originally meant "one by one," with by apparently denoting succession; modern sense of "before long" is from 1520s.

By and large "in all its length and breadth" (1660s) originally was nautical, "sailing to the wind and off it," hence "in one direction then another;" from nautical expression large wind, one that crosses the ship's line in a favorable direction.

late 13c., passen (transitive), "to go by (something)," also "to cross over," from Old French passer "to pass" (11c.), from Vulgar Latin *passare "to step, walk, pass" (source also of Spanish pasar, Italian passare), from Latin passus "step, pace" (from PIE root *pete- "to spread").

Intransitive sense of "to go on, to move forward, make one's way" is attested from c. 1300. The figurative sense of "to experience, undergo" (as in pass the time) is recorded from late 14c. Sense of "to go through an examination successfully" is from early 15c. Meaning "decline to do something" is attested from 1869, originally in cards (euchre). In football, hockey, soccer, etc., the meaning "to transfer the ball or puck to another player" is from c. 1865. Related: Passed; passing.

The meaning "to be thought to be something one is not" (especially in a racial sense) is from 1935, from pass oneself off(as), which is attested by 1809. The general verb sense of "to be accepted as equivalent" is from 1590s. Pass up "decline, refuse" is attested from 1896. Pass the buck is from 1865, said to be poker slang reference to the buck horn-handled knife that was passed around to signify whose turn it was to deal. Pass the hat "seek contributions" is from 1762. Pass-fail as a grading method is attested from 1955, American English.