In primary school, I was always taught that a simile is a comparison using the terms "like" or "as". I've always thought of it as an obvious metaphor, but the first way of looking at it is far more etymologically correct. Simile was borrowed in the fourteenth century from Latin, where the word was spelled the same and essentially meant the same thing. This is from similis, which literally meant "like" (in the context of a comparison, not the word used in the comparison, sadly). Through Old Latin and Proto-Italic, all of this traces back to the Proto-Indo-European reconstruction sem, meaning "together". Unsurprisingly, similis is also the etymon of our word similar, through a brief pit stop in Old French, and simulate, through Latin simulatus, meaning "to imitate". So, a simile is like a plant: it has a really cool root!
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.