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COVID-19 Terms Dictionary

These are truly unprecedented times, and it's important to stay updated on information to keep yourself apprized and educated. This dictionary will define all the terms related to COVID-19 that you need to know. 

Community Transmission

The origin or source of infection or spread of illness is unclear in a community.

Confirmed Case

The original test results of a  person with a presumptive case go to a national body for confirmation, and the second test results come back as positive. 

Contact Tracing

The process which public health officials use to identify persons who may have come in contact with someone who is infected. It involves three steps:

  1. Contact Identification- Once the infected person is identified, they’re asked bout their day-to-day activities and interactions with others.

  2. Contact Listing-  Once contacts of the infected person are identified, they’re informed of their status, and are advised to self-isolate, and seek care if necessary.

  3. Contact Follow-Up- Doctors begin to contact the people who came in contact to see if they’ve developed symptoms.


Coronaviruses are a large family of viruses, some can affect animals, and others can impact humans. Scientists have divided coronaviruses into four sub-groupings, called alpha, beta, gamma, and delta. There are 7 known strains of the coronavirus that can infect humans, 4 of which cause minor symptoms.  These 7 are:

  1. 229E (alpha)

  2. NL63 (alpha)

  3. OC43 (beta)

  4. HKU1 (beta)

  5. MERS-CoV- a beta virus that causes Middle Eastern Respiratory Syndrome (MERS)

  6. SARS-CoV- a beta virus that causes severe acute respiratory syndrome (SARS) 

  7. SARS-CoV-2- causes COVID-19


A mild to severe respiratory illness that is caused by a coronavirus, is transmitted chiefly by contact with infectious material (such as respiratory droplets) or with objects or surfaces contaminated by the causative virus, and is characterized especially by fever, cough, and shortness of breath and may progress to pneumonia and respiratory failure.


A disease that is endemic is one that re-emerges on a seasonal basis, occurring at a predictable rate in a certain area or among a set population.


A city or country where the outbreak is the most evident. 


The number of cases rises above what is expected in a specific area or region.

Flattening the Curve 

A public health strategy to slow down the spread of the SARS-CoV-2 virus during the COVID-19 pandemic. The curve being flattened is the epidemic curve, a visual representation of the number of infected people needing health care over time.

Physical Distancing

The geographical distance from person A to person B (6 feet, or 2 meters).


An acronym for “personal protective equipment”. These include; face masks, gloves isolation gowns, foot covers and eye gear. 

Presumptive Case

A presumptive case means that a local health agency has received a positive test result from a patient. But the test often needs to be validated with a second test.


Pronounced “R-naught”, it is a measurement used to depict the ferocity of an outbreak. An R0 value of 1 means that each infection will cause one new infection. If it's greater than 1, each infection will cause more than one new infection. This could create a potential epidemic. 

Resolved Case

A person who was previously infected no longer has the virus. 


This term applies to those who are experiencing symptoms or have tested positive. It means to stay isolated at home, and stay away from the general public and those who are not sick. In many instances, people use it interchangeably with “quarantine”. 


This applies to everyone, even those who have not been infected. It is when people are asked to stay home with limited exceptions, such as shopping for essentials, and exercise, all while social distancing. 

Social Distancing

A measure of the distance across social boundaries.


Strict isolation imposed to prevent the spread of disease. Separates and restricts the movement of people who were exposed to a contagious disease to see if they become sick.

Resources and References

CBC News. (2020, April 28). A COVID-19 glossary: What the terms mean and some subtle

differences | CBC News. Retrieved June 3, 2020, from https://www.cbc.ca/news/health/


Merriam-Webster, Incorporated. (2020, March 18). A Guide to Coronavirus-Related Words.

Retrieved June 3, 2020, from https://www.merriam-webster.com/words-at-play/coronavirus-


Willingham, A. J. (2020, March 11). Pandemic, COVID-19 and all the coronavirus terms you need

to know. Retrieved June 3, 2020, from https://www.cnn.com/2020/03/05/us/coronavirus-


Featured image courtesy of the Texas Medical Center

Article Contributors: Risheena Banerji, Palak Agarwal, Olivia Ye