Pylimitics

When someone is suspected of carrying a contagious disease, they might be placed in quarantine. “Quarantine” has an unexpected sound for that context; doesn’t it remind you of quarter or quartile? Well it should! “Quarantine” is derived from the French “quarante,” which means “forty.” In English when we want to say something like about forty or so, we can use the word form “fortyish.” In French it’s pretty similar, but instead of adding “-ish,” you add “-ain.” So the French source of quarantine means about forty. 

Why does about forty have anything to do with someone who’s sick, though? It’s because back in the day if a sailing ship entering port was suspected of harboring any diseases, the crew (and the cargo, for that matter) were prohibited from setting foot on land until everyone was sure there wasn’t any danger. The general rule was that if the crew was healthy after about forty days, they were okay and could come ashore. Even today, when we have a better idea of what’s going on with germs and all, a quarantine period is still pretty much about forty days.