n (chiefly uncountable) The state of being isolated, detached, or separated; the state of being away from other people.
n The act of isolating.
n (diplomacy, of a country) The state of not having diplomatic relations with other countries (either with most or all other countries, or with specified other countries).
n (chemistry) The obtaining of an element from one of its compounds, or of a compound from a mixture
n (medicine) The separation of a patient, suffering from a contagious disease, from contact with others (compare: quarantine)
n (databases) A database property that determines when and how changes made in one transaction are visible to other concurrent transactions.
n (psychology) A Freudian defense mechanism in which a person suppresses a harmful thought from developing into a train of thought.