The time from a person’s first exposure to a disease to the time when symptoms develop.

The time from a person's exposure to a pathogen to the time symptoms are developed. "This is important clinically," quoting Melissa Nolan. "It helps inform how long a person should be isolated to prevent spread of infection."

The incubation period for a disease is the time from which you're exposed to the organism – such as a virus or bacteria – by which it's caused until you develop the first symptoms. Evidence so far suggests that the incubation period for the virus that causes COVID-19 may range from two to 14 days, according to the CDC. You are contagious during this time, even if you're not yet showing symptoms, or asymptomatic.

The amount of time it takes for an infected person to start showing symptoms of illness after exposure. In the case of coronavirus, the incubation period is thought to be between two days and two weeks, with the average being five days before symptoms start to appear.

The amount of time a person carries a virus before showing symptoms. The most recent research suggests that for the coronavirus, this is 2-14 days, with an average of 5 days.