A view is a panel that can be used for any purpose. In the IDE they are used mostly to display structured data or the properties of an object.
There are a couple of views in the IDE: some of them show content related to the active editor, content related to the selected element in the workbench, or content of the project.
At this moment, the views can be resized but not dragged, docked or stacked in other places in the workbench, or closed and opened (as you can do in other IDEs). We should add those features in a future version of IDE.