euthanasia eu·tha·na·sia (yōō'thə-nā'zhə, -zhē-ə)
The act or practice of ending the life of an individual suffering from a terminal illness or an incurable condition, as by lethal injection or the suspension of extraordinary medical treatment.
A quiet, painless death.
Painlessly putting someone to death — usually someone with an incurable and painful disease; mercy killing.
Note: Proposals to make euthanasia legal in the United States have inspired heated debate.