ETYM Old Eng. along, anlong, AS. andlang, along.
1. In accompaniment or as a companion.
2. In addition (usually followed by 'with').
3. In line with a length or direction (often followed by 'by' or 'beside').
4. To a more advanced state.
5. With a forward motion; SYN. on.

1. In a line matching the length or direction of ; also; at a point or points on
2. In the course of
3. In accordance with; in