Euthanasia is a subject of permanent discussion everywhere, mainly about its ethical appropriateness and about its legalization in different countries. This debate includes many ethical, legal, social, political, spiritual, religious, and public health issues. A relevant problem is the frequent misunderstanding that many have about the meaning of the terms and concepts used in different ethical and clinical end of life settings. Many views and even texts are affected by such mistakes, rendering a constructive discussion almost impossible. The goal of this article is to contribute to an improvement of the social and legislative discussion about euthanasia through an elucidation of the main terms and notions linked to this topic. We present definitions and explanations for euthanasia, assisted suicide, withdrawal or foregoing of therapy, treatment rejection, palliative sedation, dignified death and others.