>I don't know how many other meanings 'octopus' may have, but ...

Dear Thorny Diver,

Here in Australia an "octopus strap" is a thick elastic cord (like a tiny bungee rope) with a hook at each end, used to secure loads to a roof rack or trailer. Curious name, given there's only one "leg". The full name is hardly ever heard - most people refer to them as "ocker straps" or "ockie straps". All a bit confusing, since "ocker" is Australian slang for "typically Australian". "Ockie" is purportedly slang for octopus, but I have only ever heard the word in the "ockie strap" context, never on its own for the marine creature.

Check out ocker, ockie and ocker/ockie strap at:
http://macgate.dict.mq.edu.au/p/dictionary/slang-o.html