If you’ve spent time around the astronomical literature, you’ve probably heard at least one term that made you wonder “why did astronomers do that?” G-type stars, early/late type galaxies, magnitudes, population I/II stars, sodium “D” lines, and the various types of supernovae are all members of the large, proud family of astronomy terms that are seemingly backwards, unrelated to the underlying physics, or annoyingly complicated. While it may seem surprising now, the origins of these terms were logical at the time of their creation. Today, let’s look at the history of a couple of these terms, to figure out why astronomers did that.