Yes, yes, smarty pants, I know you know what it means – it’s when a person’s (or animal’s) movement is restricted for a certain amount of time to make sure they don’t pass on any nasty diseases. But it has quite an interesting origin story. Allow me to take you back to the 17th-century. Trading ships are travelling from one country to another, sometimes bringing unwanted cargo like typhoid, cholera and yellow fever alongside their goods. In a bid to stop these spreading, authorities order them to be isolated in port for 40 days before people can come ashore. And that’s where we get the word – ‘quaranta giorni’ which literally means 40 days in Italian.
Why 40 days? No one really knows, is the short answer. And it actually started out as 30 days, and was called, unimaginatively, ‘trentino’. At some point an extra 10 days was added, possibly just as a precaution as people began to understand incubation periods a bit more. Or it might be because the number 40 has lots of Biblical significance – it was the number of days and nights J-Christ spent in the desert, and also the time Moses spent up Mount Sinai doing something very important that I can’t remember (commandments, maybe? You can tell I went to convent school can’t you?).
Interestingly (kinda), lots of us use ‘quarantine’ wrongly. You can only be quarantined if you’re not actually ill i.e. you don’t have a medical diagnosis. If you’re already sick and you have to be kept away from healthy peeps, then you’re in ‘medical isolation’, not quarantine. There’s also a thing called ‘cordon sanitaire’ which is similar, but refers to restricting people’s movement in or out of a specific geographic area to stop an infection from spreading.