IDE used for iOS and OSX development, though can handle other languages.
Identity Inspector- the third button from the left on the top of the right pane when InterfaceBuilder is open. Allows you to change class of objects in a storyboard
Attributes Inspector- fourth button from the left in the right pane when InterfaceBuilder is open. Allows editing of basic properties of selected object
Generally contains a window into code, showing the currently selected file.
Assistant Editor- shows a split view, where the right pane is automatically selected as the companion of the left pane.
Play button- runs the application on the target
Target- the simulator or device meant to run the application