Bill, act, statute, law are frequently confused when used to designate a legislative measure.
Bill is properly applied only to the draft of a measure submitted to a legislature for its acceptance or rejection. The other terms are properly applied only to bills which have been passed.
In actual use they are practically identical. Strictly, however, a bill becomes an act when it is passed and duly signed by an executive officer; an act becomes a statute when it is legally effective and a part of the written law of the state; a statute is one kind of law (see LAW).