The Arbor Knot is useful for securing the end of the fishing line to the reel spool, or arbor, prior to filling the reel. It's a very easy knot to tie, and leaves very little tag end exposed once the knot is cinched down.
1. Pass the line around the reel spool and tie an overhand knot around the standing section, leaving a long tag end.
2. Tie a second overhand knot in the tag end.
3. Tighten and trim the tag end close to the knot.
4. Pull on the standing section of line to draw the two overhand knots together and snug them up against the spool.