The ongoing tidal wave of coronavirus pandemic-related news is thick with terms like, well, “pandemic.” We know what these words mean in a general sense, but in technical terms, what is the difference between “pandemic” and “outbreak?” How about “quarantine” and “isolation?”

Below is a sampling of some common terms, grouped by similarity.

Epidemic: “an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area.” (source: the Centers for Disease Control)

Outbreak: “carries the same definition of epidemic, but is often used for a more limited geographic area.” (source: CDC)

Pandemic: “an epidemic that has spread over several countries or continents, usually affecting a large number of people.” (source: CDC)

To flatten the curve: refers to a graph modeling the spread of COVID-19. The graph may have a high peak, illustrating rapid infection, or a gradual rise and fall, illustrating a slow rate of infection. A slower infection rate will decrease the possibility of overwhelming healthcare facilities with a rush of patients in need of advanced care. (source: New York Times)

Isolation: “separates sick people with a contagious disease from people who are not sick.” (source: CDC)

Quarantine: “separates and restricts the movement of people who were exposed to a contagious disease to see if they become sick.” (source: CDC)

Social distance: “the avoidance of close contact with other people during the outbreak of a contagious disease in order to minimize exposure and reduce the transmission of infection.” (source:

A shelter-in-place order: usually a temporary order within the immediate time-frame of a discrete emergency event, this type of order directs the public to get inside the nearest building and stay there until further notice. (source: CDC)

A stay-at-home order: “under this type of order, you should remain at home and away from other people unless it’s absolutely necessary to go out.” (source: