along (adv., prep.)

Old English andlang "entire, continuous; extended" (adj.); "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 Old Norse cognate endlang. Prepositional sense extended in Old English to "through the whole length of." Of position, "lengthwise," c. 1200; of movement, "onward," c. 1300. Meaning "in company, together" is from 1580s. All along "throughout" is from 1690s.

Definitions of along

along (adv.)
in addition (usually followed by `with');
we sent them food and some clothing went along in the package
consider the advantages along with the disadvantages
along with the package came a bill
along (adv.)
in accompaniment or as a companion;
I brought my camera along
his little sister came along to the movies
working along with his father
along (adv.)
to a more advanced state;
the work is moving along
well along in their research
hurrying their education along
getting along in years
along (adv.)
in line with a length or direction (often followed by `by' or `beside');
cottages along by the river
pass the word along
ran along beside me
along (adv.)
with a forward motion;
the horse trotted along at a steady pace
we drove along admiring the view
move along
Synonyms: on