Coronavirus: What is social distancing? When should I quarantine versus isolate?

Is it coronavirus or COVID-19? Should I quarantine or isolate? How do you even "social distance" yourself?

As the new coronavirus spreads as do concerns around it, many public health terms have appeared in news headlines and made their way into every day conversations.

As of Wednesday morning, there have been 121,564 confirmed cases of the coronavirus worldwide, leaving 4,373 dead. In the United States, 1,050 have been infected, killing 29 people, according to a Johns Hopkins University tracker.

Cities have been locked down, large gatherings banned, canceled or postponed and countless people quarantined in their homes on the advice of local public health agencies and departments.

So what do all these coronavirus terms mean? Here's a guide to help you make sense of the vocabulary.

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Coronavirus

According to the U.S. Centers for Disease Control and Prevention, coronaviruses are a group of viruses that can infect humans and animals. Their name comes from crown-like spikes on their surface.

These viruses can cause a common cold or a more serious disease, including Middle East Respiratory Syndrome (MERS), severe acute respiratory syndrome (SARS) and coronavirus disease 2019 (COVID-19).

COVID-19

COVID-19 is the disease caused by the virus named SARS-CoV-2. It first appeared in Wuhan, China, in late 2019. Symptoms usually occur within 2 to 14 days of exposure and include fever, cough and shortness of breath. More serious symptoms can occur, usually when people have other medical conditions, including pneumonia.

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Epidemic

An epidemic is the rapid spread of an illness affecting a defined region or population.

Pandemic

A pandemic is a global outbreak of a serious new illness that requires “sustained transmission throughout the world," Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told USA TODAY in February.

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That's a variation of the World Health Organization's definition: "A pandemic is the worldwide spread of a new disease."

The WHO declared Wednesday that COVID-19 is a pandemic.

Quarantine

Quarantine occurs when a person is believed to have been exposed to a disease but is not symptomatic, according to the CDC. It's a way to monitor if symptoms develop and at the same time, avoid any possible spread to others. People under quarantine for possible COVID-19 might be asked to stay home and avoid going out in public for a period of 14 days.

Isolation

Isolation occurs when a person is known or believed to be infected with a disease that is potentially transmittable, according to the CDC. It's the process of separating known sick people from those who are known to be not sick. An isolated person is usually told to stay in a separate room from other people in their homes and use a separate bathroom.

"Isolation for public health purposes may be voluntary or compelled by federal, state, or local public health order," the CDC says.

Social distancing

The CDC defines social distancing as "remaining out of congregate settings, avoiding mass gatherings and maintaining distance (approximately 6 feet) from others when possible."

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Presumptive positive

A "presumptive positive" occurs when a person tests positive for the virus locally but the CDC has not yet confirmed the results. A state or local laboratory may test a respiratory specimen from a patient, but the CDC must still confirm the results.

"For public health purposes, a presumptive positive result using the CDC test is treated as a positive," the CDC says.

The CDC says it's possible that the virus won't be detected in the early stages of infection. However, in general, a negative test result when a person is symptomatic likely means the COVID-19 virus isn't causing their illness, the CDC says. 

Contributing: Joel Shannon

Follow USA TODAY's Ryan Miller on Twitter @RyanW_Miller