I only just saw this thread and I want to comment. Sorry for being late.
I should think that the basic difference is one of intent. What was the thing intended for? If it was intended as a tool, it would be a knife, if it was intended as a weapon it would be a sword. I do have one problem here, however. What is a Bowie knife? I seem to remember that its original intent was as a weapon, after the infamous Natchez Sandbar Fight. Also, original intent would be damned hard to debate with Officer Friendly or a judge.
One other point, please. Adamantium, what was the weapon of the "Night of the Long Knives" in Nazi Germany?
I should think that the basic difference is one of intent. What was the thing intended for? If it was intended as a tool, it would be a knife, if it was intended as a weapon it would be a sword. I do have one problem here, however. What is a Bowie knife? I seem to remember that its original intent was as a weapon, after the infamous Natchez Sandbar Fight. Also, original intent would be damned hard to debate with Officer Friendly or a judge.
One other point, please. Adamantium, what was the weapon of the "Night of the Long Knives" in Nazi Germany?