A science advocate responds to the criticism that “evolution is just a theory,” explaining that, for scientists, a “theory” is a thoroughly tested, well established explanation. In some venues, this is a familiar trope. Yet, not only is this completely, utterly wrong, but anyone with a brain and an internet connection can verify that it’s wrong in minutes. Instead, scientists for 200 years have used “theory” for conjectures that are not well established, even ones whose truth is rejected, e.g., Lamarck’s theory. What is going on?