In my current work in progress, Children of Clay, I use the word "euthanasia" a few times. A few critiquers have noted that I am using the word incorrectly. Euthanasia refers to "the practice of intentionally ending one's life to relieve suffering and pain" (Wiki).
I haven't researched the use of the word over the centuries but I did come across its use in the 19th century. John Henry Newman, a Catholic thinker, used the word "euthanasia" in its primary Greek form. In ancient Greek, "eu" means "well/sweet" and "thanatos" means "death." So euthanasia in its basic meaning is a "beautiful death." Newman described the death of one of dear friends this way, as a way to express that her death was saintly. He also was horrified that the word was being adopted to suicidal uses, closer to what we use today.
In Children of Clay, which features an alternate world, I use the word to capture the idea of a beautiful death. A death in which one is not passive, i.e., death does not choose you, but you choose death in order to ascend to the supreme deity.