A more thorough explanation:

Definition: Euthanasia, also known as mercy killing, is the act of ending the life of a person who is terminally ill and suffering from pain. It is different from assisted suicide, which is when a doctor helps a person end their own life. Euthanasia is more commonly used for sick or injured animals, as it is illegal in most parts of the United States for humans. Currently, only a few places in the US allow euthanasia for humans, including Oregon, Washington D.C., Hawaii, Washington, Maine, Colorado, New Jersey, California, and Vermont.

Euthanasia can be voluntary or non-voluntary. In voluntary cases, the person who is suffering consents to the ending of their life. In non-voluntary cases, the person is unable to make the decision, so a guardian or family member makes the decision for them. For example, if a person is in a coma and cannot make a decision about whether to stay on life support, their family may decide to end their life.

One example of euthanasia is when a veterinarian puts a sick or injured animal to sleep to end their suffering. Another example is when a person with a terminal illness decides to end their life with the help of a doctor in a place where euthanasia is legal. These examples illustrate the definition of euthanasia because they both involve ending the life of someone or something who is suffering and cannot be helped.