ETYM French quarantaine, Old Fren. quaranteine, from French quarante forty, Latin quadraginta, akin to quattuor four, and Eng. four: cf. Italian quarantina, quarentine. Related to Four, Quadragesima.
1. Enforced isolation to prevent spread of disease.
2. Traditionally a period of isolation of forty days (from the French quarante) to prevent the spread of infectious disease.
3. Time for which, and place where, ships, persons or animals suspected of infection are isolated.