Real Dictionary

quarantine
If a person or animal is in quarantine, they are being kept separate from other people or animals for a set period of time, usually because they have or may have a disease.
If people or animals quarantine or are quarantined, they are stopped from having contact with other people or animals. If a place is quarantined, people and animals are prevented from entering or leaving it.

quarantine in American English
the period, orig. 40 days, during which an arriving vessel suspected of carrying contagious disease is detained in port in strict isolation
to place under quarantine
noun: a strict isolation imposed to prevent the spread of disease
transitive verb: to put in or subject to quarantine

quarantine in British English
to isolate in or as if in quarantine
noun: a period of isolation or detention, esp of persons or animals arriving from abroad, to prevent the spread of disease, usually consisting of the maximum known incubation period of the suspected disease