buzzard (n.)
c.1300, from Old French buisart "buzzard, harrier, inferior hawk," from buson, buison, from Latin buteonem (nominative buteo) a kind of hawk, perhaps with -art suffix for one that carries on some action or possesses some quality, with derogatory connotation (see -ard).
buzzer (n.)
c.1600, "buzzing insect," agent noun from buzz (v.). In reference to mechanical devices that buzz, from 1870 (steam-powered at first; electric mechanisms so called from 1884).
buzzword (n.)
also buzz word, 1946, from buzz (n.) + word (n.). Noted as Harvard student slang for the key words in a lecture or reading. Perhaps from the use of buzz in the popular counting game.
BVDs (n.)
"men's underwear," 1935, from trademark name (dating to 1876) of manufacturer Bradley, Voorhees, and Day.
bwana
respectful or reverential form of address in East Africa, 1878, from Swahili.
by (prep.)
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-product (n.)
also byproduct; 1857, from by + product.
Byblos
ancient Phoenician port (modern Jebeil, Lebanon) from which Egyptian papyrus was exported to Greece. The name probably is a Greek corruption of Phoenician Gebhal, said to mean literally "frontier town" (compare Hebrew gebhul "frontier, boundary," Arabic jabal "mountain"), or perhaps it is Canaanite gubla "mountain." The Greek name also might have been influenced by, or come from, an Egyptian word for "papyrus."
bye (1)
in sporting use, a variant of by (prep). Originally in cricket, "a run scored on a ball that is missed by the wicket-keeper" (1746); later, in other sports, "position of one who is left without a competitor when the rest have drawn pairs" (1883), originally in lawn-tennis.
bye (2)
shortened form of good-bye. Reduplication bye-bye is recorded from 1709, though as a sound used to lull a child to sleep it is attested from 1630s.
bygone (adj.)
early 15c., from by (adv.) + gone. Compare similar construction of aforesaid. As a noun from 1560s (see bygones).
bygones (n.)
"things that are past," especially offenses, 1560s, from plural of noun use of bygone (q.v.).
bylaw (n.)
late 13c., bilage "local ordinance," from Old Norse or Old Danish bi-lagu "town law," from byr "place where people dwell, town, village," from bua "to dwell" (see bower) + lagu "law" (see law). So, a local law pertaining to local residents, or rule of a corporation or association. Sense influenced by by.
byline (n.)
1926, "line giving the name of the writer of an article in a newspaper or magazine;" it typically reads BY ________. From by (prep.) + line (n.). As a verb by 1958.
BYOB
initialism (acronym) for "bring your own bottle" or "bring your own booze," by 1951.
bypass (n.)
also by-pass, 1848, of certain pipes in a gasworks, from by + pass (n.). First used 1922 for "road for the relief of congestion;" figurative sense is from 1928. The heart operation was first so called 1957.
bypass (v.)
1823, "to pass by" (implied in bypassed), from bypass (n.). From 1928 as "to go around, avoid;" figurative use from 1941. Related: Bypassed; bypassing.
byre (n.)
"cow-shed," Old English byre, perhaps related to bur "cottage, dwelling, house" (see bower).
Byronic (adj.)
1823, pertaining to or resembling British poet George Gordon, 6th Baron Byron (1788-1824).
Perfect she was, but as perfection is
Insipid in this naughty world of ours,
Where our first parents never learn'd to kiss
Till they were exiled from their earlier bowers,
Where all was peace, and innocence, and bliss
(I wonder how they got through the twelve hours),
Don Jose like a lineal son of Eve,
Went plucking various fruit without her leave.

[from "Don Juan"]
bystander (n.)
1610s, from by + agent noun from stand (v.). They have been innocent at least since 1829. Stander-by is from 1540s.
byte (n.)
1956, American English; see bit (n.2). Reputedly coined by Dr. Werner Buchholz at IBM.
byway (n.)
mid-14c., from by + way (n.).
byword (n.)
also by-word, Old English biword "proverb," formed on the model of Latin proverbium or Greek parabole. Meaning "something that has become proverbial" is from 1530s.
Byzantine (adj.)
1770, from Latin Byzantinus (see Byzantium); originally used of art style; later in reference to the complex, devious, and intriguing character of the royal court of Constantinople (1937). As a noun from 1770.
Byzantium
said to be named for its 7c. B.C.E. Greek founder, Byzas of Megara.