In 1556, the word ensurance was first borrowed into the English language, meaning "betrothal" or "engagement". Soon it expanded in definition to cover assurances and pledges of all kinds (the etymon of our word ensure), then the leading e became and i, and finally a meaning of "financial security against loss" emerged by 1651, giving us our modern word insurance. Before all that, esurance was the Old French word enseurance, which could also refer to an assurance of any type. Here we can chop off the prefix en-, which meant "make", and the suffix -ance, denoting an action, which leaves us with the root sur, meaning "safe". Sur is a relative of English sure, coming from the Latin word securus, or "free from care" (the direct ancestor of "secure"). Now another prefix, se-, can be eliminated, meaning "apart", leaving cura, "care". Finally, it's all reconstructed to PIE keys, "to heed". My takeaway here is that insurance means to "make something safe" and has a ton of relatives, from ensure to cure. Fascinating stuff!
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd