1. A computer program product to manage concurrently used applications based on application state, the computer program product comprising: a non-transitory computer-readable medium having program code embodied therewith, the program code executable by one or more computer processors to: upon detecting a first state of a first application, the first state identified as bearing a historical association with a state of a second application in terms of concurrent usage, invoke the second application without requiring any user request to invoke the second application, in order to complete a first meta-application that includes the first and second applications and that excludes a third application, whereupon the state of the second application is restored; and upon detecting a second state of the first application, the second state identified as bearing a historical association with a state of the third application in terms of concurrent usage, invoke the third application without requiring any user request to invoke the third application, in order to complete a second meta-application that includes the first and third applications and that excludes the second application, whereupon the state of the third application is restored; wherein the first and second states are distinct states, wherein the states of the second and third applications are each of a respective state type selected from a plurality of state types including access to a specified file, access to a specified uniform resource locator, and access to a specified server, of which each state type is restorable, wherein at least one historical association is identifiable based at least in part on each criterion selected from a concurrent usage frequency and a concurrent usage duration, wherein the first and second meta-applications are defined based on monitoring concurrent application usage, including monitoring application states, and without requiring user input explicitly defining any meta-applications.