When the word prophylactic was first used in the English language in the 1540s, it solely referred to medicines that prevent disease. It had a myriad of spelling variations, such as prophikacticke, prophikactyke, prophylactice, prophtlactyce, prophylactick, and prophilactic, only becoming standardized during the eighteenth century. It wasn't until the 1930s that the word gained its most widely recognized definition of "rubber condom" (under a shared connection of stopping the spread of disease), since there was an increased need of euphemistic synonyms for the birth control method at the time. Through French, prophylactic is a Latinized version of the Greek word prophylaktikos, which carried a definition of "precautionary", or, more literally, "watch before". This is composed of the prefix pro-, meaning "before" (from Proto-Indo-European per) and the root phylassein, "to guard" (which has an unknown etymology but is likely Proto-Hellenic in origin).
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.