The term Darwinism has a contested history, though this fact is often hidden behind the unproblematic way in which it is deployed in a range of academic discourses, not least among evolutionists and historians of science. A favored strategy has been to reduce the meaning of Darwinism to the single mechanism of natural selection, a strategy that was promoted by neo-Darwinians in the second half of the twentieth century following the modern synthesis. Recent historians of science, who promote the notion of a “non-Darwinian Revolution,” rely on such a reduction as well by arguing that in the late nineteenth century natural selection was largely rejected by most evolutionists in favor of other, "non-Darwinian" mechanisms and forms of evolution. But Darwin himself never reduced his theory of evolution to natural selection, and neither, for that matter, did his self-described “Darwinian” defenders (e.g., Huxley, Wallace, Lyell, etc.). This paper will, therefore, bring clarity and historical specificity to “Darwinism” by examining the origins of the use of this term as well as how its meaning changed over time, focusing on the late nineteenth century when evolutionists were just grasping what “Darwinism” might mean as Darwin began writing specifically about human evolution.