travel bubble
This is a protected area within which people can travel, either from one country to another or within a small group of countries which are thought to have controlled the COVID-19 outbreak. Because they all have a low incidence of the disease they can collectively resume some activities such as air travel. At the moment the specific travel bubble being considered is the trans-Tasman travel bubble. If this is successful, then it is possible for other activities to be considered within the bubble. But there must be agreement on the safety measures required to make it work.
The first travel bubble to appear is the one encompassing Lithuania, Estonia and Latvia.