This is a very good question Willy!Â Marlinespike is the art of seamanship that includes the tying of various knots, splicing lines, working with cable or wire rope and even making decorative ornaments from rope or line.
The name marlinespike is derived from the tool that is used for splicing lines. It can be a tapered metal pin or carved from wood. It is used to open the strands of line so that other strands can be threaded through.
Did you know that once a rope is onboard a boat, and is given a specific purpose such as dock line, halyard, spring line, etc., it is called a line, not a rope?
There are many books on marlinespike and how to tie various knots that you can probably find in your local library.