Definition - What does Toxic mean?
A toxic substance is one that is capable of causing injury or death. It usually relates to a chemical substance. The effect of a toxic substance on the human body is dose dependent. The skull and cross-bones is an internationally used symbol on toxic substances. Toxicity is species dependent and individuals within a species can have different levels of reaction to a toxin.
Safeopedia explains Toxic
There are four types of toxins; chemical, biological, physical and radiation. A chemical toxin may include an inorganic substance like chlorine gas as well as organic substances including medication and poisonous secretions from living creatures. Biological toxins include bacteria and viruses that cause diseases within the body. Physical toxins are substances that, when taken into the body, impair the body's functioning. An example is coal dust. Exposure to ionizing radiation is also toxic.