"A quarantine means that a person, or people, will have to stay in isolation separated from others and avoid contact with anyone else."2. Etymology: derived from the Latin quadraginta, "forty". Originally, this referred to the amount of time a widow could remain in her deceased husband’s house, then it referred to the period of time a ship had to wait off a country’s port if its passengers were stricken with a disease. Now, a quarantine can mean a period of isolation for any length of time.
The meaning of "period a ship suspected of carrying disease is kept in isolation" is from Italian quarantina giorni; literally, "a space of forty days" from quaranta, "forty". The term comes from the Venetian custom of keeping ships that came from plague-stricken countries from entering its port for a period of 40 days.
"Martin's dog became very ill and the veteranarian immediately quarantined her."