Prebinding is an optimization process that allows faster launching of applications in Mac OS X. Often, when a program is opened, it loads data from files called dynamic libraries. These libraries must be located each time a program is run since their memory addresses are usually undefined.
When a program incorporates prebinding, the addresses of the library or libraries referenced by the program are predefined. This saves time by avoiding unnecessary searching each time the program is run. The prebinding process happens during the "Optimizing" stage of the program's installation. While prebinding make take some time, it is more efficient to do this process once, rather than each time the program is run.
Prebinding is only possible with Mach-O executable programs, since CFM PEF binaries do not support prebinding.