Rosetta is a lightweight dynamic translator for Mac OS X distributed by Apple. It enables applications compiled for the PowerPC family of processors to run on Apple systems that use Intel processors. Rosetta is based on Transitive Corporation's QuickTransit technology.

Compatibility

Mac 68K emulator - lower level program used for a similiar purpose during 680x0 to PowerPC transition.
Universal binary - combined PPC/Intel applications that run natively on both processors.
Fat binary - combined PPC/68k application that ran on older Macintoshes.