What is the meaning of along?

adverb

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