1. It’s a common misconception, but poison, toxin and venom are not interchangeable terms. Think of them instead as potentially lethal nesting dolls.
2. Poisons are any substance that can cause harm, including death, to an organism. Poisons that are not toxins include, for example, radiation, lab-engineered pesticides and lead.
3. Toxins, however, are usually defined as poisons produced by living organisms, typically as a means of defense or to subdue prey. Some toxinologists (yes, that’s the word for people who study toxins) argue that toxins are any poison that requires only a tiny dose to be harmful, but theirs is a field-specific definition.