Middle English, from Old English andlang "entire, continuous; extended" (adj.); also "alongside of" (prep.); from and- "opposite, against" (from Proto-Germanic *andi-, *anda-, from PIE *anti "against," locative singular of root *ant- "front, forehead") + lang "long" (see long (adj.)).

Reinforced by its Old Norse cognate endlang. The prepositional sense was extended in Old English to "through the whole length of." Of position, "lengthwise," from c. 1200; of movement, "onward," from c. 1300. The meaning "in company, together" is from 1580s. All along "throughout" is attested from 1690s.

1959, noun and adjective, from verbal phrase; see sing (v.) + along (adv.). Originally associated with U.S. music producer Mitch Miller (1911-2010).

"agree, live harmoniously," 1875, from get (v.) + along (adv.).

also fire-bomb, 1895 (earlier as a type of fireworks and a type of cannonball), from fire (n.) + bomb (n.). As a verb, from 1950 as an act of vandalism or terrorism, from 1941 as a military aviation tactic. Related: Firebombed; firebombing.

"existing or employed along a shore or coast," 1779, from along + shore (n.). Compare along-ships (adv.) "lengthwise to the ship" (1680s), alongside.

1550s, "cannonball" (a sense now obsolete), from French boulette "cannonball, small ball," diminutive of boule "a ball" (13c.), from Latin bulla "round thing, knob" (see bull (n.2)). The meaning "small ball," specifically a metal projectile meant to be discharged from a firearm, is from 1570s. Earliest version of the figurative phrase bite the bullet "do something difficult or unpleasant after delay or hesitation" is from 1891, probably with a sense of giving someone a soft lead bullet to clench in the teeth during a painful operation.

Beggars' bullets—stones thrown by a mob, who then get fired upon, as matter of course. [John Bee, "Slang," 1823]

"alluvial land along the margin of a river," 1752, American English, from river (n.) + bottom (n.).

"going along with, adjoining," by 1782, present-participle adjective from accompany (v.).

"to furnish with a tag," late 14c. (implied in tagged), from tag (n.1). Meaning "go along as a follower" is from 1670s; sense of "follow closely and persistently" is from 1884. Related: Tagging. Verbal phrase tag along is first recorded 1900.

"along the course of a missile, spacecraft, etc.," 1952, from down (adv.) + range (n.).