Toxin (noun)

1. A poison or other harmful substance produced by living organisms.
2. A toxic substance that can cause harm or death to living organisms.

Origin:

The word toxin comes from the greek word "toxikon" which means poison for arrows.

Examples:

1. The bacteria produces a potent toxin that can cause severe food poisoning.
2. The venom of the snake contains several different toxins.
3. The shellfish contains a dangerous neurotoxin that can cause paralysis.
4. The toxin can cause damage to the liver and kidneys.
5. A tetanus toxin is produced by the bacteria Clostridium tetani.