A rubber cord with hooks on both ends, wrapped in cloth to protect the cord and to keep the cord from scuffing things.
Most people know it as the thing you tie your trunk lid down with when something you are carrying in your car is far too large to allow the trunk to close properly.
Generally useful in mobile freight applications.
Anti-Spurious-Downvote-Disclaimer: Yes, I am aware that some people like to spell it "BUNGEE". But I've always spelled it this way. So that would be that.
This definition is correct -- Tem42