When you throw a ball, you toss it using your hand. When you throw a party, you buy some food and drinks, then invite your friends over.
Throw means many things. You can throw a baseball game, even if you're not the pitcher, by deliberately trying to lose it. You can throw a baby off its schedule — that is, confuse the baby's waking and sleeping times. In basketball, when you get fouled and throw the ball from the free-throw line, you're taking a free throw. You can throw garbage out. Also, a throw is a small blanket you toss over a chair, much like a throw pillow.