"natural earthen incline bordering a body of water," c. 1200, from a Scandinavian source such as Old Norse *banki, Old Danish banke "sandbank," from Proto-Germanic *bankon "slope," cognate with *bankiz "shelf" (see bench (n.)). As "rising ground in a sea or rover, shoal," from c. 1600. As "bench for rowers in an ancient galley," 1590s.

There probably was an Old English cognate but it is not attested in surviving documents. The nasalized form likely is a variant of Old Norse bakki "(river) bank, ridge, mound; cloud bank," cognate with Swedish backe, Danish bakke "hill, rising ground."

c. 1200, "piece of cloth attached to the upper end of a pole or staff," from Old French baniere "flag, banner, standard" (12c., Modern French bannière), from Late Latin bandum "standard," borrowed from Frankish or another West Germanic source, from Proto-Germanic *bandwa- "identifying sign, banner, standard," also "company under a banner" (source also of Gothic bandwa "a sign"), from suffixed form of PIE root *bha- (1) "to shine."

Formerly the standard of a king, lord, or knight, behind which his followers marched to war and to which they rallied in battle. The figurative sense of "anything displayed as a profession of principles" is from early 14c. Of newspaper headlines that stream across the top of the page, from 1913.

c. 1200, "one who baptizes," also (with capital B-) a title of John, the forerunner of Christ; see baptize + -ist. As "member of a Protestant sect that believes in adult baptism upon profession of faith," generally by full immersion (with capital B-), attested from 1654; their opponents called them anabaptists (see Anabaptist).

"utter an abrupt, explosive cry" (especially of dogs), Middle English berken (c. 1200), bark (late 15c.), from Old English beorcan "to bark," from Proto-Germanic *berkan (source also of Old Norse berkja "to bark"), of echoic origin. Related: Barked; barking.

To bark at the moon "complain uselessly" is from 1650s. To bark up the wrong tree "mistake one's object, attack or pursue something other than what is intended" is U.S. colloquial, attested by 1832, from notion of hounds following the wrong scent.

c. 1200, "a member of the nobility," also a low rank in the peerage, from Old French baron (nominative ber) "baron, nobleman, military leader, warrior, virtuous man, lord, husband," probably from or related to Late Latin baro "man" (source of Spanish varon, Italian barone), which is of uncertain origin. It is perhaps from Celtic or from Frankish *baro "freeman, man" or another Germanic source. In England the word merged with (probably) cognate Old English beorn "nobleman."

c. 1200, "incapable of producing its kind" (of female animals, plants), from Old French baraigne, baraing "sterile, barren" (12c.), perhaps originally brahain, a word of obscure derivation, possibly from a Germanic language. Its use in reference to males is rare. Of land, "producing little or no vegetation," by late 14c.

As a noun from mid-13c., "a barren woman;" later "tract of more or less unproductive land."

BARRENS. Elevated lands, or plains upon which grow small trees, but never timber. [Bartlett, "Dictionary of Americanisms," 1848]

"large shallow vessel or dish used chiefly to hold water or other liquid," c. 1200, from Old French bacin (11c., Modern French bassin), from Vulgar Latin *baccinum (source also of Spanish bacin, Italian bacino), from *bacca "water vessel," perhaps originally Gaulish (but OED dismisses the proposed Celtic cognates on sense grounds). The meaning "large-scale artificial water-holding landscape feature" is from 1712. The geological sense of "tract of country drained by one river or draining into one sea" is from 1830.

"a stick or staff used in beating, a war-club, staff used to strike the ball in certain games," c. 1200, from rare Old English batt "cudgel," a western England word at first, probably from Welsh or another Celtic source (compare Irish and Gaelic bat, bata "staff, cudgel"), later reinforced and influenced by Old French batte "pestle," from Late Latin battre "to beat;" all from PIE root *bhat- "to strike." As a kind of wooden paddle used to play cricket (later baseball), it is attested from 1706.

A Middle English sense of "a lump, piece, chunk" (mid-14c.) was used in reference to bread, clay, wool, and survives in brickbat and batting (n.1). 

The phrase right off the bat (1866), also hot from the bat (1870), probably represent a baseball metaphor, but cricket or some other use of a bat might as easily be the source—there is an early citation from Australia (in an article about slang): "Well, it is a vice you'd better get rid of then. Refined conversation is a mark of culture. Let me hear that kid use slang again, and I'll give it to him right off the bat. I'll wipe up the floor with him. I'll ---" ["The Australian Journal," November 1888].

c. 1200, beste, "one of the lower animals" (opposed to man), especially "a four-footed animal," also "a marvelous creature, a monster" (mermaids, werewolves, lamia, satyrs, the beast of the Apocalypse), "a brutish or stupid man," from Old French beste "animal, wild beast," figuratively "fool, idiot" (11c., Modern French bête), from Vulgar Latin *besta, from Latin bestia "beast, wild animal," which is of unknown origin.

The word was used in Middle English to translate Latin animal. It displaced Old English deor (see deer) as the generic word for "wild creature," only to be ousted 16c. by animal.

c. 1200, "brutish, sensual, debased;" late 14c., "in the manner of a beast," from beast + -ly (1). It weakened in British upper crust use to "awfully, exceedingly" by mid-19c. Beastly drunk is from 1794.

Beastly expresses that which is altogether unworthy of a man, especially that which is filthy and disgusting in conduct or manner of life. Bestial is applied chiefly to that which is carnal, sensual, lascivious: as, bestial vices or appetites. [Century Dictionary]