There is a significant difference between REBUILT and REMANUFACTURED parts, though many people erroneously believe the two terms to be synonymous. Any part that is NOT "OEM" (Original Equipment Manufacturer), falls under one of four categories:
While new and used is rather self-explanatory, rebuilt and remanufactured are different, and usually carry different warranties.
"Remanufacturing" disassembles a core system or assembly so that the subsystems and components can be cleaned, tested, repaired/reworked or replaced. The components are then reassembled and tested so the performance of the reassembled equipment can be tested and warranted.
Rebuilding a part involves replacing only the broken or unusable components in a system or assembly, without a complete disassembly and inspection. A remanufactured alternator, for example, may have new diodes, new brushes, an undercutting of the armature coil, new bearings and pulleys, to work about as good as a new one. A rebuilt one may only have the brushes replaced. Because of this, rebuilt parts have short warranty periods, typically 30 days to 90 days) while a remanufactured assembly will have a much longer warranty, some as long as 1-year or even "lifetime".
Engine replacements are a bit more complicated, and most quality engines will carry an AERA, ARC, or similar decal to identify that the engine has been rebuilt either using new parts, re-machining of those parts still re-usable, and subject to rigorous testing and inspection standards. Some engines and engine assemblies are labelled as 'Remanufactured in the USA' for example, meaning that it was rebuilt in the US, using primarily American sourcing for parts. The same holds for 'Remanufactured in Canada'.