Are swords Basically just much bigger knives ?

Of course not, knives are just much smaller swords.

No. Swords, knives and any weapons are extensions of your arms. If you cannot think of them as such, then they are not going to be of any use to you.

lmfao.......

man the trolling this morning on here,  its insane XD

By that reasoning spears would be knives as well. 

The major difference other than size is the edge. On a typical western (E.G. European) sword the cutting edge is actually a bit blunt, compared to most knives. ... Machetes are basically a really big knife, because their edge is made to slash through things like vines, leaves, and small branches.

That's like asking if a stool is a chair. It depends

Yes and No. It depends on the function. There are knives that have over 18 inch blade and swords with blades as short as 20 inches, roughly. There are single edged and double edged knives and swords.

What abt daggers? Are they short swords or long knives?

It all depends on the function and your training as well. What your comfortable with and what you train with on a regular. In some cases techniques are so similar all it is is a weapons change thats it. In some cases it does not transition well and yu have to modify. Or it just doesn't seem logical or does not work.

Another is staff and spear? Are they same or different? Actually all the forms and techniques are identical. All that is different is the weapon and the application of..

There are certain differences, obviously.  A sword is not designed for a sawing motion as are some knives.  Some swords are designed primarily to stab instead of to slice.  Since they are used in combat scenarios they are designed sometimes to have hand protectors.  Some are designed more for show than for use in actual fighting.  Sword-fighting is a complex technique requiring much skill and practice to learn properly and effectively.  Most people above a certain age can use knives for their intended purposes with no or little practice.

Well a sword is a blade like a knife three and a half 4 ft long some as long as 6 ft long.  It's also heavier than a knife. A sword is not a hacking instrument if you hack with a sword you're not going to get much done.  But sliding your sword as if it was a very long knife well you can cut pretty deep if you do that