In general, a quarantine is “a strict isolation imposed to prevent the spread of disease.” We know what you might be thinking: so, a quarantine is … just an isolation? Not exactly.
As the Centers for Disease Control and Prevention (CDC) explains, the practice of a quarantine specifically involves:
The takeaway: People are put in quarantine when they are not currently sick, but have been or may have been exposed to a communicable disease. This can help stop the spread of the disease.
Voluntary quarantine (when someone isn’t ordered to go into quarantine but chooses to do so just out of caution) is often called self-quarantine.
Entering English in the early 1600s, this “isolation” sense of quarantine comes from the Italian quarantina, a period of forty days, derived from quaranta, the Italian for “forty.” (The Italian quaranta, if you’re curious, comes from the Latin quadrāgintā, also meaning “forty.”)
What’s so special about 40? Historically, a quarantine referred to a period—originally of 40 days—imposed upon ships when suspected of carrying an infectious or contagious disease. This practice was done in Venice in the 1300s in an effort to stave off the plague