Web framework
A Web application framework is a set of software tools to make it easier to create Web applications. They typically provide functionality such as database access, templating, and session management.
Such tools range from simple libraries, such as DBI, or the much larger PEAR, to systems using Model-view-controller concepts, where the mere structure of the data is all that need to be specified to create a fully-functional application.
For example, when programming a to-do list as a web application, it is often sufficient for a programmer to specify "each user can have many tasks, each of which has a description, a date, and a priority" and the web application framework will turn that description into a program capable of adding, editing, listing, and deleting tasks from a database.
The term web application framework can also describe tools which are not specific to web applications, but can be used for them (such as .NET)