Burstable Bandwidth

From HostPedia

Burstable bandwidth is a more flexible alternative to dedicated bandwidth, it means that a dedicated bandwidth is being divided between various servers in order to save on bandwidth costs.

For example, a web hosting company which hosts multiple sites from all over the world can save money on wasted bandwidth by dividing it's bandwidth between multiple websites. Since each site has visitors from different countries, the traffic spread through the day and it is still possible to serve all these sites with little or no connectivity problems.