Coronavirus: a general term to describe a set of viruses whose molecular structure looks like a wreath of particles; “corona” is Latin for “wreath” or “crown.” Other diseases caused by coronaviruses include MERS (Middle East Respiratory Disease) and SARS (Severe Acute Respiratory Syndrome). For more, visit the Johns Hopkins University’s School of Medicine explainer.

COVID-19: the infectious disease discovered last November in Wuhan, China as a result of a novel (new) coronavirus. The acronym COVID-19 derives from the letters CO and V (for coronavirus), I for infectious, D for disease and 19 for 2019, the year of discovery.

Disease versus virus: A virus replicates itself in a host’s DNA. In this case, the coronavirus causes COVID-19 disease. The disease is an infection that can occur in the lungs or other organs. For more on what COVID-19 does on the body, read this article from The New York Times.

CDC: Centers for Disease Control and Prevention, a United States federal government agency that works to identify, research, and mitigate infectious diseases.

WHO: World Health Organization, a body that is funded by the United Nations to identify and research all types of health issues, from diabetes to heart disease and other infectious diseases. WHO issues guidance to countries to combat them.

Flatten the Curve: This term refers to the goal of reducing the amount of infections that occur all at once. By doing so, the health system won’t get overwhelmed. Here is an article from The Washington Post that illustrates the idea.

Social Distancing: Voluntary separation from other people, especially further than 6 feet. Avoiding crowds and public spaces is also part of this practice. This may not be because those who practice social distancing are contagious; it is a preventative measure to flatten the curve. Read more about it from the PBS NewsHour here.


Self-Isolation: related to social distancing, isolation and quarantine help protect the public by preventing exposure to people who have or may have a contagious disease. Self-isolation is a choice an individual makes, often with the recommendation of a doctor, to isolate themselves from the public due to possibly having or having been exposed to a contagious disease.

Quarantine: a state, period, or place of isolation in which people or animals that have arrived from elsewhere or been exposed to infectious or contagious disease are placed. People may employ “self-quarantining” where, similar to self-isolation and social distancing, people choose to quarantine themselves if they suspect they might be contagious or symptomatic of COVID-19.

Shelter-in-place: An edict by municipalities (local city governments) that directs all citizens to stay in their homes. Exceptions include health or emergency workers or officials in essential fields like police or power companies.

Epidemic: An increase, often sudden, in the number of cases of a disease above what is normally expected in a  population.

Outbreak: The same definition of epidemic, but is often used for a more limited geographic area where a disease might break out.

Pandemic: An epidemic that has spread over several countries or continents, usually affecting a large number of people. “Pan” is Greek for “everywhere” or “all” and the root word, “demos” means “people.” The WHO’s definition is here.

Influenza or Flu: “flu” is short for “influenza.” Influenza is a disease that has many strands and severity levels. Coronavirus is similar to the flu, in that it has similar symptoms. But they are not the same. A notable type of the flu was the H1N1 or “Swine” flu, which was pervasive in 2009.

H1N1 or Swine Flu: H1N1 is an influenza virus that causes a respiratory illness and is referred to as Swine Flu because it originated in pigs. In 2009-2010, there was a Swine Flu pandemic that resulted in an estimated 61 million cases and 12,500 deaths in the United States, according to the CDC. While the pandemic is over, H1N1 continues to circulate seasonally.      

Vaccine: A substance used to stimulate the production of antibodies (blood proteins in the body that attack viruses or bacteria) and provide immunity against one or several diseases. It is not a cure, but a preventative measure.

Contact Tracing: Monitoring those who have had contact with or exposure to an infected person to find patients that may not know they are infected. By testing those who have been in contact with known carriers of the virus, public health officials can reduce inadvertent spreading.

Incubation period: the time from exposure to the virus until the first symptoms develop. During this period, one may not feel symptoms of the disease but may still be able to spread it.

Sources: CDC; WHO; Johns Hopkins University’s School of Medicine; The Washington Post; The New York Times; PBS NewsHour