venom and poison do not equal same thing. they are both toxic but the difference is how they are delivered.
poison is normally used as a defensive mechanism by passive prey animals (frogs, toads, insects) to avoid being killed/eaten
venom is mainly used by predators to kill prey
poison can be inhaled, absorbed, or swallowed
venom HAS to be entered via the blood stream which is why it goes hand in hand with biting (or in a jellyfish, it is administered via needle like tentacles)
this is why you can safely suck the venom out of a snake bite. (You could also probably drink a cup of venom and be ok provided you have no cuts in your mouth)
Venom is a specialized type of poison, that has been evolved for a specific purpose.
However ... referring to organisms, being venomous and poisonous have different meanings. Venomous means the organism actively injects its prey with poison. Poisonous means the organism is toxic to touch or eat. Some organisms can be both.
Sort of like those women who file overlapping (and utterly frivolous) restraining orders against their beaus, thereby putting a damper on the whole romance/love/affair/lust interlude thing, right?
(I have to create these narrowly-focused analogies in my mind in order to conceptualize the greater world that exists outside the vicinity of my crotchular area.)