i tend to differ in opinion. It states that the venom is something that is transmitted by bite or sting...which means it affects the injured, intravenously so to speak. Whereas, poison, is secreted from an animals body and will affect you by touching or swallowing it.
venom is derived from venous which means: of veins
In essence, yes, venom is poison, in terms of it being toxic to the body. But I think the difference is in the way it is administered.