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A bundle is a directory in the file system that groups related resources together in one place. Applications, frameworks, and plug-ins are all examples of bundles. Programs can also use document bundles instead of flat files to save complex content.
Many bundles are also packages, that is, they are presented to the user as opaque files rather than as directories. This opaqueness has advantages for both users and developers. For users, it simplifies the user’s interaction with applications and other bundles and makes it harder to delete critical resources accidentally. For developers, it simplifies the software distribution process.
Both Cocoa and Core Foundation provide API for accessing the contents of a bundle. For more information on accessing bundles from Cocoa, see the NSBundle class documentation. For information on accessing bundles from Core Foundation, see the CFBundle reference.
For information about framework bundles, see Framework Programming Guide.