In Jira 7 release notes what is an application?

[C]

how does the licensing work?   What is an application?

are plugins now called applications?  What is core?

• Licensing - JIRA 7.0 eliminates the single JIRA license in favor of a base platform where multiple applications can be licensed individually. You can install one or more applications in JIRA via the Manage applications page. The base JIRA application, JIRA Core, provides basic project tracking capabilities for business teams. All JIRA applications include access to JIRA Core, or you can license JIRA Core only for users that need basic access to JIRA.

[teilor_soares · Accepted solution]

The Agile and Service Desk plugins are now applications.

JIRA 7 divided in 3 products.

JIRA Core (for business teams)

JIRA Software (for dev teams, with all Agile tools)

JIRA Service Desk (for service desk team)

If you have JIRA Core installed, you can add a Application to your instance, like JIRA Software or JIRA Service Desk, and set the users able to access this new application.

As a example, you will not have anymore to purchase an Agile license for all your users in JIRA, you can just purchase the number of licenses you need to attend your dev team.

Cheers!
Teilor